Sample records for light beam polarization

In this work we present a setup for the experimental production of cylindrically polarizedbeams, as well as other variations of polarizedlightbeams. The optical system uses a single transmissive phase-only spatial light modulator, which is used to apply different spatial phase modulation to two output collinear R and L circularly polarized components. Different cylindrically polarizedlightbeams can be obtained by applying different phase shifts to these two circularly polarized components. The system is very efficient since modulation is directly applied to the lightbeam (as opposed to other common methods operating in the first order of encoded diffraction gratings). Different variations to the cylindrically polarizedlightbeams are also reported, obtained by adding linear or quadratic relative phase shifts between the two circular polarization components of the lightbeam. Experimental results are provided in all cases.

Metamaterials have attracted a lot of attention in the past decade, because of its remarkable properties in electronics and photonics. Recently, a new kind of two-dimensional metamaterial named metasurface have led the research front. Metasurfaces show up excellent optical properties by patterning planar nanostructures. Novel optical phenomena based on graphene include ultra-thin focusing, anomalous reflection or refraction strong spin-orbit and so on. In this work, we have designed a novel infrared lightpolarizedbeam splitter by combining the 2D array of graphene with a subwavelength-thickness optical cavity, which demonstrated great splitting effect in infrared wavelength. Our demonstration pave a novel way for the infrared lightpolarizedbeam splitting.

The edge diffraction of a homogeneously polarizedlightbeam is studied theoretically based on the paraxial optics and Fresnel-Kirchhoff approximation, and the dependence of the diffracted beam pattern of the incident beampolarization is predicted. If the incident beam is circularly polarized, the trajectory of the diffracted beam center of gravity exhibits a small angular deviation from the geometrically expected direction. The deviation is parallel to the screen edge and reverses the sign with the polarization handedness; it is explicitly calculated for the case of a Gaussian incident beam with a plane wavefront. This effect is a manifestation of the spin-orbit interaction of light and can be interpreted as a revelation of the internal spin energy flow immanent in circularly polarizedbeams. It also exposes the vortex character of the weak longitudinal field component associated with the circularly polarized incident beam.

Polarized laser has been widely used in free space optical communication, laser radar, and laser ranging system because of its advantages of good performance in recent years. The changes of laser polarization properties in the process of transmission in atmospheric turbulence have a certain impact on the system performance. The paper research on the rule of polarization properties changes of Gauss Schell model beam in turbulent conditions. And analysis the main factors to affect the polarization properties by numerical simulation using MATLAB software tools. The factors mainly including: initial polarization, coherence coefficient, spot size and the intensity of the atmospheric turbulent. The simulation results show that, the degree of polarization will converge to the initial polarization when the beam propagation in turbulent conditions. The degrees of polarization change to different value when initial polarization of beam is different in a short distance. And, the degrees of polarization converge to the initial polarization after long distance. Beam coherence coefficient bigger, the degree of polarization and change range increases bigger. The change of polarization more slowly for spot size is bigger. The change of polarization change is faster for longer wavelength. The conclusion of the study indicated that the light source parameters effect the changes of polarization properties under turbulent conditions. The research provides theory basis for the polarization properties of the laser propagation, and it will plays a significant role in optical communication and target recognition.

We present the directional beaming effect of light at the terahertz frequency by using a subwavelength slit in the metal film. The metal is dressed with anisotropic dielectric so that both the transverse electric (TE) and transverse magnetic (TM) polarized waves can be well guided on the metal surface and reach the phase matching. By using a periodical array of dielectric ridges and grooves around the slit, the guided waves can be scattered out of the slit and interfere with the transmitted light directly through the slit. The results performed by finite-difference at time-domain computations indicate that the directional beaming of light can be obtained simultaneously for both the TE and TM polarized waves after optimizing the geometric parameters. The structure may find great applications in polarization-independent optical devices such as couplers, connectors, beam collimator, and etc.

A beam splitter with a two-layer metal-dielectric structure in a Michelson interferometer is considered. It is shown that introduction of an additional dielectric interference layer makes it possible to reduce significantly (in comparison with a beam splitter with one metal layer) the difference in the reflectance from the side of air, the reflectance from the side of substrate, and the transmittance for p-polarizedlight, with conservation of a 90° phase shift for two outputs.

We construct the manifold describing the family of plane monochromatic light waves with all directions, polarizations, phases and intensities. A smooth description of polarization, valid over the entire sphere S^2 of directions, is given through the construction of an orthogonal basis pair of complex polarization vectors for each direction; any lightbeam is then uniquely and smoothly specified by giving its direction and two complex amplitudes. This implies that the space of all lightbeams is the six dimensional manifold S^2 X C^2, the Cartesian product of a sphere and a two dimensional complex vector space. A Hopf map (i.e mapping the two complex amplitudes to the Stokes parameters) then leads to the four dimensional manifold S^2 X S^2 which describes beams with all directions and polarization states. This product of two spheres can be viewed as an ordered pair of two points on a single sphere, in contrast to earlier work in which the same system was represented using Majorana's mapping of the states of a ...

We construct the manifold describing the family of plane monochromatic light waves with all directions, polarizations, phases and intensities. A smooth description of polarization, valid over the entire sphere S{sup 2} of directions, is given through the construction of an orthogonal basis pair of complex polarization vectors for each direction; any lightbeam is then uniquely and smoothly specified by giving its direction and two complex amplitudes. This implies that the space of all lightbeams is the six dimensional manifold S{sup 2}×C{sup 2}∖(0), the (untwisted) Cartesian product of a sphere and a two dimensional complex vector space minus the origin. A Hopf map (i.e. mapping the two complex amplitudes to the Stokes parameters) then leads to the four dimensional manifold S{sup 2}×S{sup 2} which describes beams with all directions and polarization states. This product of two spheres can be viewed as an ordered pair of two points on a single sphere, in contrast to earlier work in which the same system was represented using Majorana’s mapping of the states of a spin one quantum system to an unordered pair of points on a sphere. This is a different manifold, CP{sup 2}, two dimensional complex projective space, which does not faithfully represent the full space of all directions and polarizations. Following the now-standard framework, we exhibit the fibre bundle whose total space is the set of all lightbeams of non-zero intensity, and base space S{sup 2}×S{sup 2}. We give the U(1) connection which determines the geometric phase as the line integral of a one-form along a closed curve in the total space. Bases are classified as globally smooth, global but singular, and local, with the last type of basis being defined only when the curve traversed by the system is given. Existing as well as new formulae for the geometric phase are presented in this overall framework. -- Highlights: • We construct a polarization basis for light which is smooth in all

Reflection and refraction of monochromatic light by an air-dielectric interface at an incidence angle below the Brewster angle can generate split beams of equal power and orthogonal polarizations under certain achievable conditions. Generation of photon streams of orthogonal polarizations, previously thought to be possible mainly by double refraction in anisotropic crystals, is achieved for an infinite set of input states that leads to a correspondingly infinite set of pairs of orthogonal output states. A bare substrate of PbTe is particularly suitable for this beam splitting function in the IR. However, use of a high-refractive-index quarter-wave layer on a low-refractive-index substrate extends the operating range of this interesting device to a much wider spectral range including the visible.

Full Text Available A novel polarimeter based on the asymmetry in the spatial distribution of synchrotron radiation (SR will make for a fine addition to the existing Møller and Compton polarimeters. The spin light polarimeter consists of a set of wiggler magnet along the beam that generate synchrotron radiation. The spatial distribution of synchrotron radiation will be measured by ionization chambers. The up-down (below and above the wiggle spatial asymmetry in the transverse plain is used to quantify the polarization of the beam. As a part of the design process, effects of a realistic wiggler magnetic field and an extended beam size were studied. The perturbation introduced by these effects was found to be negligible. Lastly, a full fledged GEANT-4 simulation was built to study the response of the ionization chamber (IC.

A novel polarimeter based on the asymmetry in the spacial distribution of synchrotron radiation will make for a fine addition to the existing M{\\o}ller and Compton polarimeters. The spin light polarimeter consists of a set of wiggler magnet along the beam that generate synchrotron radiation. The spacial distribution of synchrotron radiation will be measured by ionization chambers. The up-down (below and above the wiggle) spacial asymmetry in the transverse plain is used to quantify the polarization of the beam. As a part of the design process, effects of a realistic wiggler magnetic field and an extended beam size were studied. The perturbation introduced by these effects was found to be negligible. Lastly, a full fledged GEANT-4 simulation was built to study the response of the ionization chamber.

The physics program at the upgraded Jefferson Lab (JLab) and the physics program envisioned for the proposed electron-ion collider (EIC) include large efforts to search for interactions beyond the Standard Model (SM) using parity violation in electroweak interactions. These experiments require precision electron polarimetry with an uncertainty of < 0.5 %. The spin dependent Synchrotron radiation, called "spin-light," can be used to monitor the electron beampolarization. In this article we develop a conceptual design for a "spin-light" polarimeter that can be used at a high intensity, multi-GeV electron accelerator. We have also built a Geant4 based simulation for a prototype device and report some of the results from these simulations.

The physics program at the upgraded Jefferson Lab (JLab) and the physics program envisioned for the proposed electron-ion collider (EIC) include large efforts to search for interactions beyond the Standard Model (SM) using parity violation in electroweak interactions. These experiments require precision electron polarimetry with an uncertainty of $light," can be used to monitor the electron beampolarization. In this article we develop a conceptual design for a "spin-light" polarimeter that can be used at a high intensity, multi-GeV electron accelerator. We have also built a Geant4 based simulation for a prototype device and report some of the results from these simulations.

A new technique for coding and decoding of optical signals through the use of polarization is described. In this technique the concept of coding is translated to polarization. In other words, coding is done in such a way that each code represents a unique polarization. This is done by implementing a binary pattern on a spatial light modulator in such a way that the reflected light has the required polarization. Decoding is done by the detection of the received beam's polarization. By linking the concept of coding to polarization we can use each of these concepts in measuring the other one, attaining some gains. In this paper the construction of a simple point-to-point communication where coding and decoding is done through polarization will be discussed.

Optical singularities manifesting at the center of vector vortex beams are unstable, since their topological charge is higher than the lowest value permitted by Maxwell's equations. Inspired by conceptually similar phenomena occurring in the polarization pattern characterizing the skylight, we show how perturbations that break the symmetry of radially symmetric vector beams lead to the formation of a pair of fundamental and stable singularities, i.e. points of circular polarization. We prepare a superposition of a radial (or azimuthal) vector beam and a uniformly linearly polarized Gaussian beam; by varying the amplitudes of the two fields, we control the formation of pairs of these singular points and their spatial separation. We complete this study by applying the same analysis to vector vortex beams with higher topological charges, and by investigating the features that arise when increasing the intensity of the Gaussian term. Our results can find application in the context of singularimetry, where weak fi...

We propose a simple method for generating and controlling right- and left-handed circularly polarized (RHP and LHP) multiring modes of lightbeams by means of Pockels effect in a single strontium barium niobate (SBN) crystal. The numerical results show that an LHP Laguerre-Gaussian LG(0l) beam, propagating along the optical axis of the crystal, will partly turn into an RHP vortex light field of order l+2. Moreover, a pair of the LHP and RHP components of the output light field is LG-like modes sharing an identically radial index, which is electro-optically controllable. The power ratio between these two components depends on the applied electric field and the mode of input beam.

The well-known effects of the spin-orbit interactions of light are manifestations of the pair's mutual influence of the three types of angular momentum (AM) of light, namely, the spin AM, the extrinsic orbital AM and the intrinsic orbital AM. Here we propose a convenient classification of the effects of the spin-orbit interactions of light and we observe one of the new effects in the frame of this classification, which is determined by the joint influence of two types of the AM on the third type of the AM, namely, the influence of the spin AM and the extrinsic orbital AM on the intrinsic orbital AM. We experimentally studied the propagation of circularly polarizedlight through an optical fiber coiled into a helix. We have found that the spin AM and the helix parameters affect the spatial structure of the radiation transmitted through the optical fiber. We found out that the structure of the light field rotates when changing the sign of circular polarization. The angle of rotation depends on the parameters of the helix. The results can be used to develop the general theory of spinning particles and can find application in metrology methods and nanooptics devices.

The well-known effects of the spin-orbit interaction of light are manifestations of pair mutual influence of the three types of the angular momentum of light, namely, the spin angular momentum, the extrinsic orbital angular momentum and the intrinsic orbital angular momentum. Here we propose the convenient classification of the effects of the spin-orbit interaction of light and we observe one of the new effects in the frame of this classification, which is determined by the joint influence of two types of the angular momentum on the third type of the angular momentum, namely, the influence of the spin angular momentum and the extrinsic orbital angular momentum on the intrinsic orbital angular momentum. We experimentally studied the propagation of circularly polarizedlight through an optical fiber coiled into a helix. We have found that the spin angular momentum and the helix parameters affect the spatial structure of the radiation transmitted through the optical fiber. We found out that the structure of the ...

It is shown that a laser can efficiently accelerate charged particles if a magnetic field is introduced to improve the coupling between the particle and the wave. Solving the relativistic equations of motion for an electron in a uniform magnetic field and superposed, circularly polarized electromagnetic wave, it is found that in energy-position phase space an electron traces out a curtate cycloid: it alternately gains and loses energy. If, however, the parameters are chosen so that the electron's oscillations in the two fields are resonant, it will continually accelerate or decelerate depending on its initial position within a wavelength of light. A laboratory accelerator operating under these resonant conditions appears attractive: in a magnetic field of 10,000 gauss, and the fields of a 5 x 10 to the 12th W, 10 micron wavelength laser, an optimally positioned electron would accelerate to 700 MeV in only 10 m.

Eleven demonstrations of lightpolarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

We demonstrate a coherent quantum measurement for the determination of the degree of polarization (DOP). This method allows to measure the DOP in the presence of fast polarization state fluctuations, difficult to achieve with the typically used polarimetric technique. A good precision of the DOP measurements is obtained using 8 type II nonlinear crystals assembled for spatial walk-off compensation.

Linearly polarizedlight passing through a several micron thick magnetooptic film in the inhomogeneous magnetization state is split into a linearly polarized central beam and linearly polarized first and higher order diverging rings. The polarization of the central output beam lies in the same direction as the linearly polarized input, while the polarization of the diverging rings lies in a direction orthogonal to the input plane of polarization. The effect is described, and applications of the effect are discussed.

Liquid crystal grating with three-dimensionally modulated anisotropic structure is fabricated by one-step exposure of an empty glass cell whose inner walls are coated with photocrosslinkable polymer liquid crystals to four-beampolarization interference UV beams. The diffraction properties were probed with a 633 nm wavelength laser and a 532 nm wavelength laser which were the coaxial incident. The novel properties, which diffraction directions are threedimensionally different depending on the wavelengths, are realized by the resultant liquid crystal grating. Furthermore, the resultant liquid crystal grating can be also applied to an advanced polarizingbeam splitter which opposite circular polarization and linear polarizations are diffracted simultaneously. These diffraction properties were well-explained by Jones calculus. The resultant liquid crystal grating has the plural of the functions of optical elements such as wave plates, polarizationbeam splitter, dichroic beam splitter, Wollaston/Rochon prism, and tunable wavelength filter. Therefore, the resultant liquid crystal grating can contribute to miniaturization, sophistication, and cost reduction of optical systems using for, such as optical measurement, communication, and information processing.

The data on polarizedlight (PS) - a new promising treatment, rehabilitation and prevention, which took its deserved place among the known therapeutic physical factors and may even compete with laser radiation of low and LED therapy...

Describes three demonstrations used in the Chicago Museum of Science and Industry polarizedlight show. The procedures employed are suitable for the classroom by using smaller polarizers and an overhead projector. Topic areas include properties of cellophane tape, nondisappearing arrows, and rope through a picket fence. (JN)

Describes three demonstrations used in the Chicago Museum of Science and Industry polarizedlight show. The procedures employed are suitable for the classroom by using smaller polarizers and an overhead projector. Topic areas include properties of cellophane tape, nondisappearing arrows, and rope through a picket fence. (JN)

The optical spin torque (OST) induced by vector Bessel (vortex) beams can cause a particle to rotate around its center of mass. Previous works have considered the OST on a Rayleigh absorptive dielectric sphere by a vector Bessel (vortex) beam, however, it is of some importance to analyze the OST components for a sphere of arbitrary size. In this work, the generalized Lorenz-Mie theory (GLMT) is used to compute the OST induced by vector Bessel (vortex) beams on an absorptive dielectric sphere of arbitrary size, with particular emphasis on the beam order, the polarization of the plane wave component forming the beam, and the half-cone angle. The OST is expressed as the integration of the moment of the time-averaged Maxwell stress tensor, and the beam shape coefficients (BSCs) are calculated using the angular spectrum decomposition method (ASDM). Using this theory, the OST exerted on the light-absorptive dielectric sphere in the Rayleigh, Mie or the geometrical optics regimes can be considered. The axial and transverse OSTs are numerically calculated with particular emphasis on the sign reversal of the axial OST and the vortex-like character of the transverse OST, and the effects of polarization, beam order, and half-cone angle are discussed in detail. Numerical results show that by choosing an appropriate polarization, order and half-cone angle, the sign of the axial OST can be reversed, meaning that the sphere would spin in opposite handedness of the angular momentum carried by the incident beam. The vortex-like structure of the total transverse OSTs can be observed for all cases. When the sphere moves radially away from the beam axis, it may rotate around its center of mass in either the counter-clockwise or the clockwise direction. Conditions are also predicted where the absorptive sphere experiences no spinning. Potential applications in particle manipulation and rotation in optical tweezers and tractor beams would benefit from the results.

These images taken through the wide angle camera near closest approach in the deep near-infrared methane band, combined with filters which sense electromagnetic radiation of orthogonal polarization, show that the light from the poles is polarized. That is, the poles appear bright in one image, and dark in the other. Polarizedlight is most readily scattered by aerosols. These images indicate that the aerosol particles at Jupiter's poles are small and likely consist of aggregates of even smaller particles, whereas the particles at the equator and covering the Great Red Spot are larger. Images like these will allow scientists to ascertain the distribution, size and shape of aerosols, and consequently, the distribution of heat, in Jupiter's atmosphere.

Polarizedlight microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarizedlight microscopy, often

Technique for detection of polarizedlight based on observation of scene through two stacked polarizing disks. No need to rotate polarizers to create flicker indicative of polarization. Implemented by relatively simple, lightweight apparatus. Polarization seen as bow-tie rainbow pattern. Advantageous for detecting polarization in variety of meteorological, geological, astronomical, and related applications.

The analytical and numerical basis for describing scattering properties of media composed of small discrete particles is formed by the classical electromagnetic theory. Although there are several excellent textbooks outlining the fundamentals of this theory, it is convenient for our purposes to begin with a summary of those concepts and equations that are central to the subject of this book and will be used extensively in the following chapters. We start by formulating Maxwell's equations and constitutive relations for time- harmonic macroscopic electromagnetic fields and derive the simplest plane-wave solution that underlies the basic optical idea of a monochromatic parallel beam of light. This solution naturally leads to the introduction of such fundamental quantities as the refractive index and the Stokes parameters. Finally, we define the concept of a quasi-monochromatic beam of light and discuss its implications.

Local shaping of the polarization state of a lightbeam is appealing for a number of applications. This can be achieved by employing devices containing birefringent materials. In this article, we present one such enables converting a uniformly circularly polarizedbeam into a cylindrical vector beam (CVB). This device has been fabricated by exploiting the POLICRYPS (POlymer-LIquid CRYstals-Polymer-Slices) photocuring technique. It is a liquid-crystal-based optical diffraction grating featuring polar symmetry of the director alignment. We have characterized the resulting CVB profile and polarization for the cases of left and right circularly polarized incoming beams.

The invention relates to a method and a system for synthesizing a set of controllable lightbeams by provision of a system for synthesizing a set of lightbeams, comprising a spatially modulated light source for generation of electromagnetic radiation with a set of replicas of a predetermined......(x-xs, y-ys), a Fourier transforming lens for Fourier transforming the electromagnetic radiation, a first spatial light modulator for phase shifting the Fourier transformed electromagnetic radiation with the phase -F(u, v) of S*, S* is the complex conjugate of the Fourier transformed symbol s, a Fourier...... transforming lens for Inverse Fourier transforming the spatially modulated radiation, whereby a set of lightbeams are formed propagating through the inverse Fourier plane (x', y') at desired positions (x's, y's), and a controller for controlling the position of a replica of the symbol, s, for movement...

A polarization sensitive optical imaging system is used to detect changes in polarization in dental tissues to aid the diagnosis of dental disease such as caries. The degree of depolarization is measured by illuminating the dental tissue with polarizedlight and measuring the polarization state of the backscattered light. The polarization state of this reflected light is analyzed using optical polarimetric imaging techniques. A hand-held fiber optic dental probe is used in vivo to direct the incident beam to the dental tissue and collect the reflected light. To provide depth-resolved characterization of the dental tissue, the polarization diagnostics may be incorporated into optical coherence domain reflectometry and optical coherence tomography (OCDR/OCT) systems, which enables identification of subsurface depolarization sites associated with demineralization of enamel or bone.

For the first time a vertically polarized electron beam has been used for physics experiments at MAMI in the energy range between 180 and 855 MeV. The beam-normal single-spin asymmetry An, which is a direct probe of higher-order photon exchange beyond the first Born approximation, has been measured in the reaction 12C (e → , e ‧)12C . Vertical polarization orientation was necessary to measure this asymmetry with the existing experimental setup. In this paper we describe the procedure to orient the electron polarization vector vertically, and the concept of determining both its magnitude and orientation with the available setup. A sophisticated method has been developed to overcome the lack of a polarimeter setup sensitive to the vertical polarization component.

Axial and transverse radiation force cross-sections of optical tractor Bessel polarizedbeams are theoretically investigated for a dielectric sphere with particular emphasis on the beam topological charge (or order), half-cone angle and polarization. The angular spectrum decomposition method (ASDM) is used to derive the non-paraxial electromagnetic (EM) field components of the Bessel beams. The multipole expansion method using vector spherical harmonics is utilized and appropriate beam-shape coefficients are derived in order to compute the radiation force cross-sections. The analysis has no limitation to a particular range of frequencies such that the Rayleigh, Mie or geometrical optics regimes can all be considered effectively using the present rigorous formalism. The focus of this investigation is to identify some of the tractor beam conditions so as to achieve retrograde motion of a dielectric sphere located arbitrarily in space. Numerical computations for the axial and transverse radiation force cross-sections are presented for linear, right-circular, radial, azimuthal and mixed polarizations of the individual plane waves forming the Bessel beams of zeroth- and first-order (with positive or negative helicity), respectively. As the sphere shifts off the beam's axis, the axial pulling (tractor) force is weakened. Moreover, the transverse radiation force cross-section field changes with the sphere's size factor ka (where k is the wavenumber and a is the sphere radius). Both stable and unstable equilibrium regions around the beam's axis are found, depending on the choice of ka and the half-cone angle α0. These results are particularly important in the development of emergent technologies for the photophoretic assembly of optically-engineered (meta)materials with designed properties using optical tractor (vortex) beams, particle manipulation, levitation and positioning, and other applications.

A scheme is proposed to design a polarization grating that splits an incident linearly polarizedbeam to an array of linearly polarizedbeams of identical intensity distribution and various azimuth angles of linear polarization. The grating is equivalent to a wave plate with space-variant azimuth angle and space-variant phase retardation. The linear polarization states of all split beams make the grating suitable for coherent beam combining architectures based on Dammann gratings.

Polarization effects are investigated for collisions of high-energy ..gamma.. beams produced from the Compton scattering of laser light on electrons. To do this, were obtained Stokes parameters Xisub(i), xisub(j) tilde of the ..gamma..-beams, and their average values (xisub(i)), (xisub(j) tilde), as functions of the photon energies and polarizations of the initial beams. The quantities to be measUred in the ..gamma gamma.. collisions are expressed via the average values (xisub(i)xisub(j) tilde), which are in general different from (Hisub(i))(xisub(j) tilde), the fact making the investigation of the polarization effects more complicated. In particular, (xi/sub 3/xi/sub 3/ tilde-xi/sub 11/ tilde) not equal to 0 even if the electron and the laser beams are not Polarized. It is shown that (xisub(i)xisub(j) tilde) approximately (xisub(i))(xisub(j) tilde) for two important limiting cases. Effects due to a correlation between the beams are considered.

We report three-dimensional tomographic reconstruction of optical parameters for the mesoscopic light scattering regime from experimentally obtained datasets by using polarizedlight. We present a numerically inexpensive approximation to the radiative transfer equation governing the polarizedlight transport. This approximation is employed in the reconstruction algorithm, which computes two optical parameters by using parallel and perpendicular polarizations of transmitted light. Datasets were obtained by imaging a scattering phantom embedding highly absorbing inclusions. Reconstruction results are presented and discussed.

One of the most attractive hypothesis for the origin of homochirality in terrestrial bio-organic compounds (L-amino acid and D-sugar dominant) is nominated as "Cosmic Scenario"; a chiral impulse from asymmetric excitation sources in space triggered asymmetric reactions on the surfaces of such space materials as meteorites or interstellar dusts prior to the existence of terrestrial life. 1) Effective asymmetric excitation sources in space are proposed as polarized quantum beams, such as circularly polarizedlight and spin polarized electrons. Circularly polarizedlight is emitted as synchrotron radiation from tightly captured electrons by intense magnetic field around neutron stars. In this case, either left-or right-handed polarizedlight can be observed depending on the direction of observation. On the other hand, spin polarized electrons is emitted as beta-ray in beta decay from radioactive nuclei or neutron fireballs in supernova explosion. 2) The spin of beta-ray electrons is longitudinally polarized due to parity non-conservation in the weak interaction. The helicity (the the projection of the spin onto the direction of kinetic momentum) of beta-ray electrons is universally negative (left-handed). For the purpose of verifying the asymmetric structure emergence in bio-organic compounds by polarized quantum beams, we are now carrying out laboratory simulations using circularly polarizedlight from synchrotron radiation facility or spin polarized electron beam from beta-ray radiation source. 3,4) The target samples are solid film or aqueous solution of racemic amino acids. 1) K.Kobayashi, K.Kaneko, J.Takahashi, Y.Takano, in Astrobiology: from simple molecules to primitive life; Ed. V.Basiuk; American Scientific Publisher: Valencia, 2008. 2) G.A.Gusev, T.Saito, V.A.Tsarev, A.V.Uryson, Origins Life Evol. Biosphere. 37, 259 (2007). 3) J.Takahashi, H.Shinojima, M.Seyama, Y.Ueno, T.Kaneko, K.Kobayashi, H.Mita, M.Adachi, M.Hosaka, M.Katoh, Int. J. Mol. Sci. 10, 3044

We study polarization effects in collisions of high energy ..gamma.. beams obtained in the Compton scattering of laser light on electrons (according to the scheme of I. F. Ginzburg et al., Preprint 81-50, IYaF SO AN SSSR, Novosibirsk, 1981, and JETP Letters 34, 491 (1982)). For this we determine the Stokes parameters of the ..gamma.. beams xi/sub i/ and xi-tilde/sub j/ and their average values and as functions of the photon energy and polarization of the initial beams. The quantities that are measurable in ..gamma gamma.. collisions are expressed in terms of the average values , which, in general, are not equal to , which complicates the study of polarization phenomena. In particular, not =0, even for unpolarized electron and laser beams. It is shown that in two important limiting cases roughly-equal. Effects due to correlation between the beams are studied.

We demonstrate a slow lightbeam splitter using rapid coherence transport in a wall-coated atomic vapor cell. We show that particles undergoing random and undirected classical motion can mediate coherent interactions between two or more optical modes. Coherence, written into atoms via electromagnetically induced transparency using an input optical signal at one transverse position, spreads out via ballistic atomic motion, is preserved by an antirelaxation wall coating, and is then retrieved in outgoing slow light signals in both the input channel and a spatially-separated second channel. The splitting ratio between the two output channels can be tuned by adjusting the laser power. The slow lightbeam splitter may improve quantum repeater performance and be useful as an all-optical dynamically reconfigurable router.

A high-index quarter-wave layer (QWL) embedded in a low-index cube prism is designed to achieve 50%-50% beam splitting for incident p-polarizedlight at a 45° angle of incidence. This is accomplished when the ratio of the refractive index of the QWL to that of the prism is n=3.336666. Such a refractive index ratio is realized, e.g., with a Ge QWL embedded in a LiF cube at 8.357 μm wavelength. Spectral, angular, and film-thickness sensitivities of this mid-IR beam splitter (BS) are presented. Free-standing QWL pellicles of GaP and GaAs can also function as 50%-50% BSs for incident p-polarizedlight at 45° at visible and IR wavelengths of 0.610 μm and 2.929 μm, respectively. An application in interferometry is briefly discussed.

The application of very sensitive electronic detecting devices during the last decade has revolutionized and revitalized the study of polarization in celestial objects. The nature of polarization, how polaroids work, interstellar polarization, dichroic filters, polarization by scattering, and modern polarimetry are among the topics discussed. (JN)

The author discusses research involving polarized proton beams since the ZGS`s demise. He begins by reminding the attendee that in 1973 the ZGS accelerated the world`s first high energy polarized proton beam; all in attendance at this meeting can be proud of this accomplishment. A few ZGS polarized proton beam experiments were done in the early 1970`s; then from about 1976 until 1 October 1979, the majority of the ZGS running time was polarized running. A great deal of fundamental physics was done with the polarizedbeam when the ZGS ran as a dedicated polarized proton beam from about Fall 1977 until it shut down on 1 October 1979. The newly created polarization enthusiats then dispersed; some spread polarized seeds al over the world by polarizingbeams elsewhere; some wound up running the High Energy and SSC programs at DOE.

We experimentally generate an Airy beam with polarization structure while keeping its original amplitude and phase profile intact. This class of Airy beam preserves the acceleration properties. By monitoring their initial polarization structure we have provided insight concerning the self-healing mechanism of Airy beams. We investigate both theoretically and experimentally the self-healing polarization properties of the space-variant polarized Airy beams. Amplitude as well as the polarization structure tends to reform during propagation in spite of the severe truncation of the beam by finite apertures.

Metasurface is an effective tool for smanipulating optical wave and can be used to generate vector beams. In this work, we propose a method to realize the operation of the polarization order of vector beams with cascaded metasurfaces. Employing Jones calculation, we theoretically analyze the transformation of cascaded metasurfaces for linearly polarized incident light. The results show that two directly cascaded metasurfaces can realize the subtraction operation of polarization order of vector beam. When a half-wave plate is inserted between the two metasurfaces, the addition operation of polarization order can be achieved. Lastly, verification experiments are performed. The experimental results are in good agreement with the theoretical predictions.

Presents a lesson that introduces students to polarizedlight using a problem-solving approach. After illustrating the concept using a slinky and poster board with a vertical slot, students solve the problem of creating a polarizedlight show using Polya's problem-solving methods. (MDH)

Full Text Available The data on polarizedlight (PS - a new promising treatment, rehabilitation and prevention, which took its deserved place among the known therapeutic physical factors and may even compete with laser radiation of low and LED therapy. It is reflected the significant contribution of domestic scientists in the study of aircraft action on the body, its introduction in the treatment, rehabilitation and prevention of grippe, ARI. These action's mechanisms of the aircraft on the electro-physiological processes in the body that have the leading role in the regulation of its life. The new moment in the study of aircraft on the body is the evidence of its positive impact on the mechanisms of self body - its different units: the disease's banning - a revitalization of the stress-protective, stress-limiting system antioxidial, detoxification and other protection systems, the formation by the body antiviral and antimicrobial specific substances (interferon and lysozyme, activation of the immune system, phagocytosis, protective functions of skin. The protective and mobilizing role of the second link is studied: which is triggered in case of occurrence of disease or preexisting diseases: PL mobilized processes of restitution, reparations, compensation, immunity and microcirculation. The authors studied the possibility of aircraft's using to enhance performance, reduce side effects of physical factors, which are often used in the treatment (electric methods, treatment by sound, fresh and mineral water, etc..

The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge.

The Jones calculus is a well known method for analyzing the polarization of a fully polarizedbeam. It deals with a beam having spatially homogeneous polarization. In recent years, axially symmetric polarizedbeams, where the polarization is not homogeneous in its cross section, have attracted great interest. In the present article, we show the formula for the rotation of beams and optical elements on the angularly variant term-added Jones calculus, which is required for analyzing axially symmetric beams. In addition, we introduce an extension of the Jones calculus: use of the polar coordinate basis. With this calculus, the representation of some angularly variant beams and optical elements are simplified and become intuitive. We show definitions, examples, and conversion formulas between different notations.

Polarization gratings can be recorded in bacteriorhodopsin films by an orthogonal pair of linearly or circularly polarizedbeams. If a linearly polarized auxiliary violet light is added during the grating formation, the grating becomes polarization-sensitive. A theoretical model based on the two-state photochromic theory is proposed to calculate the diffraction efficiency kinetics of these polarization gratings. In both cases, the additional linearly polarized auxiliary violet irradiation improves the steady-state diffraction efficiency and leads to a cosine modulation of the steady-state diffraction efficiency by the polarization orientation of the readout beam. Experiment results demonstrate the correctness of the theoretical model.

Discusses a demonstration of interference phenomena using three sheets of polaroid material, a light source, and a light meter. Describes instructional procedures with mathematical expressions and a diagram. (YP)

Polarized positron beams have been identified as either an essential or a significant ingredient for the experimental program of both the present and next generation of lepton accelerators (JLab, Super KEK B, ILC, CLIC). An experiment demonstrating a new method for producing polarized positrons has been performed at the Continuous Electron Beam Accelerator Facility at Jefferson Lab. The PEPPo (Polarized Electrons for Polarized Positrons) concept relies on the production of polarized e⁻/e⁺ pairs from the bremsstrahlung radiation of a longitudinally polarized electron beam interacting within a high-Z conversion target. PEPPo demonstrated the effective transfer of spin-polarization of an 8.2 MeV/c polarized (P~85%) electron beam to positrons produced in varying thickness tungsten production targets, and collected and measured in the range of 3.1 to 6.2 MeV/c. In comparison to other methods this technique reveals a new pathway for producing either high-energy or thermal polarized positron beams using a relatively low polarized electron beam energy (~10MeV) .This presentation will describe the PEPPo concept, the motivations of the experiment and high positron polarization achieved.

One of the intensity limiting factor of RHIC polarized proton beam is the electron cloud induced pressure rise. A beam scrubbing study shows that with a reasonable period of time of running high intensity 112-bunch proton beam, the pressure rise can be reduced, allowing higher beam intensity.

The acceleration of highly polarized electron beams are widely used in state-of-the-art high-energy physics experiments. In this work, a model for investigation of polarization dynamics of electron beams in the laser-plasma accelerator depending on the initial energy of electrons was developed and tested. To obtain the evolution of the trajectory and momentum of the electron for modeling its acceleration the wakefield structure was determined. The spin precession of the beam electron was described by Thomas-Bargman-Michel-Telegdi equations. The evolution of the electron beampolarization was investigated for zero-emittance beams with zero-energy spread.

We describe considerations regarding the spin filtering method for the antiproton beam. The proposed investigation of the double polarization cross section for antiproton to nucleon interaction is outlined. It will use a single path of the antiproton beam through a dense polarized target, e.g. 3He or CH2, followed by a polarimeter.

Accuracy of a radiometer is adversely affected by scene polarization if the receiving optical system is sensitive to polarization. It is therefore necessary to specify and measure the sensitivity of the system to polarizedlight. The Mueller-Stokes matrix of an instrument may be determined experimentally and used to predict the effects of the instrument on any beam. The specification of a maximum polarization sensitivity stated in terms of the degree of polarization produced in an unpolarized beam can be experimentally verified even though an unpolarized beam is not available in the laboratory for direct measurement.

A method for obtaining small bottle lightbeams,e.g.0.92λ×0.4λ,in a high numerical-aperture lens system is proposed and numerically demonstrated.This can be achieved by changing the radius of each zone of the binary element and polarization rotation angle of the cylindrically polarized vectorial vortex beam.It is found that the transversal and axial sizes of this bottle bearn are equal to about 0.92λ and 0.4λ,respectively.In addition,the connection between angular momentum and topological Pancharatnam charge is also shown.

The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge. - Highlights: • We investigated the polarization properties of modified parabolic scaling Bessel beams with linear polarization. • We studied the evolution of transverse intensity profiles for the three components of these beams. • The intensity patterns of the cross polarization and longitudinal components can reflect the sign of the topological charge.

Traditionally, the angular momentum of light is calculated for "bullet-like" electromagnetic wave packets, although in actual optical experiments "pencil-like" beams of light are more commonly used. The fact that a wave packet is bounded transversely and longitudinally while a beam has, in principle, an infinite extent along the direction of propagation, renders incomplete the textbook calculation of the spin/orbital separation of the angular momentum of a lightbeam. In this work we demonstrate that a novel, extra surface part must be added in order to preserve the gauge invariance of the optical angular momentum per unit length. The impact of this extra term is quantified by means of two examples: a Laguerre-Gaussian and a Bessel beam, both circularly polarized.

In recent years, high energy physicists have become increasingly interested in the possible spin effects at high energies. To study those spin effects, it is desirable to have beams with high energy, high intensity and high polarization. In this talk, we briefly review the present status and the prospects for the near future of high energy polarizedbeams. 30 refs.

The polarization properties of light emission from InGaN nanowire (NW) light-emitting diodes (LEDs) have been studied with the use of goniometric setup. A maximum polarization ratio of ∝0.7 has been obtained from the edge emission of NW array-based LEDs and the light is mainly polarized parallel to the c-axis of NWs. The nearly isotropic polarization response from a core-shell NW LED structure is also observed, and it is found that the degree of polarization is strongly depended on the NW diameter. With the growth of the AlGaN shell, the resulting diameter of core-shell NWs becomes larger and is comparable to the emission wavelength, thus weakening the optical confinement effect and the polarization behavior. The size-dependent polarization properties of NW structures are further verified by the finite-difference time-domain simulation. NWs with diameters much less than the emission wavelength render a strong contrast between the p- and s-polarizedlight emissions. (Left) FE-SEM image of MBE-grown NWs covered with polyimide. (Right) Plot of integrated electroluminescence intensity as a function of polarizer angle for a NW LED. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A polarizerbeam line at the radioactive beams facility ISAC at TRIUMF is nearly complete. Initially for sup 8 Li sup + ions for beta-NMR studies in condensed matter, it can in principle supply three or more experiments simultaneously, and the technique used is practicable with all alkali-metal ion beams. An atomic beam, created with over 90% efficiency by passing the initial unpolarized 30 keV beam through a sodium vapor jet target, will be polarized by colinear optical pumping. A novel feature is that the atomic beam is reionized with demonstrated high efficiency in a helium gas target. The emittance growth through the helium cell has been measured for stable sup 7 Li sup + beam on a test stand and found to be small. We report these measurements as a function of helium flow rates. A preliminary polarized sup 8 Li sup + run is planned for May, 2000.

Bessel beams are widely used in optical metrology mainly because of their large Rayleigh range (focal length). Radial/azimuthal polarization of such beams is of interest in the fields of material processing, plasma absorption or communication. In this paper an experimental set-up is presented, which generates a Bessel-type vector beam with a spatial polarization, oscillating along the optical axis, when propagating in free space. A first holographic axicon (HA) HA1 produces a normal, linearly polarized Bessel beam, which by a second HA2 is converted into the spatial oscillating polarizedbeam. The theory is briefly discussed, the set-up and the experimental results are presented in detail.

Bessel beams are widely used in optical metrology mainly because of their large Rayleigh range (focal length). Radial/azimuthal polarization of such beams is of interest in the fields of material processing, plasma absorption or communication. In this paper an experimental set-up is presented, which generates a Bessel-type vector beam with a spatial polarization, oscillating along the optical axis, when propagating in free space. A first holographic axicon (HA) HA1 produces a normal, linearly polarized Bessel beam, which by a second HA2 is converted into the spatial oscillating polarizedbeam. The theory is briefly discussed, the set-up and the experimental results are presented in detail.

The variation of polarization distribution of reflected beam at specular interface and far field caused by spin separation has been studied. Due to the diffraction effect, we find a distinct difference of lightpolarization at the two regions. The variation of polarization distribution of reflected light provides a new method to measure the spin separation displacement caused by Spin Hall Effect of light.

When elliptically polarizedlight of appropriate wavelength Corresponding to trans-cis-trans isomerisation process is incident on thin films of azobenzene polyesters, a helical structure is induced. We investigate the propagation of the exciting lightbeam (self-induced) as well as a probe light...

The use of a birefringent graded photonic crystal (GPhC) is proposed for the realization of an efficient polarizationbeam splitter. This approach allows decoupling the two functions of efficient light injection for both polarizations and TE/TM beam splitting. A smooth lightpolarization splitting is naturally achieved due to the different curved trajectories followed within the graded medium by the TE and TM waves. A 160 nm operating bandwidth with insertion loss around 1 dB and interpolarization crosstalk below -15 dB is predicted by a finite difference time domain simulation. The unusually exploited electromagnetic phenomena are experimentally evidenced by scanning near-field optical measurements performed on samples fabricated using the silicon on insulator photonics technology. These experimental works open perspectives for the use of birefringent GPhCs to manage polarization diversity in silicon photonic circuits.

POLAR is a compact polarimeter dedicated to measure the polarization of GRBs between 50-300 keV. The light collection of 200*6*6mm3 plastic bars has been simulated and optimized in order to get uniform response to x-rays at different points of one single bar. According to the Monte Carlo results, the amplitude uniformity strongly depends on the polishing level of scintillator surface and the covering. A uniformity of 89% is achieved with a prototype constructed by a non position-sensitive PMT and an array of 4X4 bars.

We report the experimental demonstration of the induced polarization-dependent optical vortex beams. We use the Talbot configuration as a method to probe this effect. In particular, our simple experiment shows the direct measurement of this observation. Our experiment can exhibit clearly the combination between the polarization and orbital angular momentum (OAM) states of light. This implementation might be useful for further studies in the quantum system or quantum information.

. A transition route based on experimental results for the theoretically calculated energy level scheme is proposed. Physical observations of surface relief in thin films of azobenzene polymers when irradiated with polarizedlight are reported. These include two beampolarization holographic observations...... and single beam transmission measurements through a mask, followed by atomic force microscope and profiler investigations. It is concluded that none of the prevalent theories can explain all the observed facts....

In this thesis we investigate devices needed to handle the polarization of thermal neutron beams: Ï/2-flippers (to start/stop Larmor precession) and Ï-flippers (to reverse polarization/precession direction) and illustrate how these devices are used to investigate the properties of matter and of the

We recently studied the spin flipping of a vertically polarized, stored 139-MeV proton beam. To flip the spin, we induced an rf depolarizing resonance by sweeping our rf solenoid magnet's frequency through the resonance frequency. With multiple spin flips, we found a polarization loss of 0.0000+/-0.0005 per spin flip under the best conditions; this loss increased significantly for small changes in the conditions. Minimizing the depolarization during each spin flip is especially important because frequent spin flipping could significantly reduce the systematic errors in stored polarized-beam experiments.

Full Text Available Polarized positron beams are in some respect mandatory complements to polarized electron beams. The advent of the PEPPo concept for polarized positron production opens the possibility for the developement at the Jefferson Laboratory of a continuous polarized positron beam. The benefits of such a beam for hadronic structure studies are discussed, together with the technical and technological challenges to face.

Polarized positron beams are in some respect mandatory complements to polarized electron beams. The advent of the PEPPo concept for polarized positron production opens the possibility for the developement at the Jefferson Laboratory of a continuous polarized positron beam. The benefits of such a beam for hadronic structure studies are discussed, together with the technical and technological challenges to face.

The geometric Spin Hall Effect of Light (geometric SHEL) amounts to a polarization-dependent positional shift when a lightbeam is observed from a reference frame tilted with respect to its direction of propagation. Motivated by this intriguing phenomenon, the energy density of the lightbeam is decomposed into its Cartesian components in the tilted reference frame. This illustrates the occurrence of the characteristic shift and the significance of the effective response function of the detector. We introduce the concept of a tilted polarizing interface and provide a scheme for its experimental implementation. A lightbeam passing through such an interface undergoes a shift resembling the original geometric SHEL in a tilted reference frame. This displacement is generated at the polarizer and its occurrence does not depend on the properties of the detection system. We give explicit results for this novel type of geometric SHEL and show that at grazing incidence this effect amounts to a displacement of multiple...

We present a convenient method to generate vector beams of light having polarization singularities on their axis, via partial spin-to-orbital angular momentum conversion in a suitably patterned liquid crystal cell. The resulting polarization patterns exhibit a C-point on the beam axis and an L-line loop around it, and may have different geometrical structures such as \\qo{lemon}, \\qo{star}, and \\qo{vortex}. Our generation method allows us to control the radius of L-line loop around the central C-point. Moreover, we investigate the free-air propagation of these fields across a Rayleigh range.

We present a convenient method to generate vector beams of light having polarization singularities on their axis, via partial spin-to-orbital angular momentum conversion in a suitably patterned liquid crystal cell. The resulting polarization patterns exhibit a C-point on the beam axis and an L-line loop around it, and may have different geometrical structures such as "lemon", "star", and "spiral". Our generation method allows us to control the radius of L-line loop around the central C-point. Moreover, we investigate the free-air propagation of these fields across a Rayleigh range.

A polarizingbeam splitter(PBS)and a non-polarizingbeam splitter(NPBS)based on a photonic crystal(PC)directional coupler are demonstrated.The photonic crystal directional coupler consists of a hexagonal lattice of dielectric pillars in air and has a complete photonic band gap.The photonic band structure and the band gap map are calculated using the plane wave expansion(PWE)method.The splitting properties of the splitter are investigated numerically using the finite difference time domain(FDTD)method.

Here we propose a novel scheme in which depolarized or unpolarized light can respond to polarization-dependent optical elements such as an input-polarization-dependent wavelength-selective filter. An optical apparatus for realizing the proposed scheme consists of a polarizationbeam splitter, two Faraday rotators, and four waveplates. By harnessing the polarization decomposition/superposition property of a polarization-diversity loop and the irreciprocity of optical Faraday rotation, we could make unpolarized light selectively excite one of the two principal axes of a polarization-dependent element like polarized one while maintaining the unpolarized nature. The principle of operation of this apparatus was theoretically analyzed through the investigation of the polarization variation of light passing through the optical elements comprising it. Then, its polarization-selective feature was experimentally verified by employing a long-period fiber grating inscribed on polarization-maintaining fiber, which had polarization-dependent spectral dips with different resonance wavelengths, as a polarization-dependent element in the polarization-diversity loop. One of the two spectrally separated resonances of the grating could be freely chosen through the proper control of the waveplates in the apparatus.

Great hopes rest on surface plasmon polaritons' (SPPs) potential to bring new functionalities and applications into various branches of optics. In this paper, we demonstrate a pin cushion structure capable of coupling light from free space into SPPs, split them based on the polarization content of the illuminating beam of light, and focus them into small spots. We also show that for a circularly or randomly polarizedlight, four focal spots will be generated at the center of each quarter circle comprising the pin cushion device. Furthermore, following the relation between the relative intensity of the obtained four focal spots and the relative position of the illuminating beam with respect to the structure, we propose and demonstrate the potential use of our structure as a miniaturized plasmonic version of the well-known four quadrant detector. Additional potential applications may vary from multichannel microscopy and multioptical traps to real time beam tracking systems.

The spin Hall effect of light originates from spin-orbit interaction of light, which manifests two types of geometric phases. In this paper, we report the observation of a geometric spin Hall effect by generating a lightbeam with inhomogeneous polarization distribution. Unlike the previously reported geometric spin Hall effect observed in a tilted beam-detector system, which is believed to result from an effective spin-redirection Berry geometric phase, the geometric spin Hall effect demonstrated here is attributed to an effective, spatially varying Pancharatnam-Berry geometric phase generated by the inhomogeneous polarization geometry. Our further experiments show that the geometric spin Hall effect can be tuned by tailoring the polarization geometry of light, demonstrating the spin states of photons can be steered with a great flexibility.

We present a study of radially and azimuthally polarized Bessel-Gauss beams in both the paraxial and nonparaxial regimes. We discuss the validity of the paraxial approximation and the form of the nonparaxial corrections for Bessel-Gauss beams. We show that, independently from the ratio between the Bessel aperture cone angle $\\vartheta_0$ and the Gauss beam divergence $\\theta_0$, the nonparaxial corrections are always very small and therefore negligible. Explicit expressions for the nonparaxial vector electric field components are also reported.

Alternative handedness and sign conventions for relating the orientation of elliptical polarization are discussed. The discussion proceeds under two headings: (1) snapshot picture, where the emphasis for the convention is contained in the concept of handedness; and (2) angular momentum consideration, where the emphasis for the convention is strongly associated with mathematical convention and the sign of the fourth Stokes parameter.

Utilizing the inverse design engineering method of topology optimization, we have realized high-performing all-silicon ultra-compact polarizationbeam splitters. We show that the device footprint of the polarizationbeam splitter can be as compact as similar to 2 µm2 while performing experimentally...... with a polarization splitting loss lower than similar to 0.82 dB and an extinction ratio larger than similar to 15 dB in the C-band. We investigate the device performance as a function of the device length and find a lower length above which the performance only increases incrementally. Imposing a minimum feature...... size constraint in the optimization is shown to affect the performance negatively and reveals the necessity for light to scatter on a sub-wavelength scale to obtain functionalities in compact photonic devices....

We convert a linearly polarized Gaussian beam into a radially polarized doughnut beam with an eight-segment spirally varying retarder (SVR) at wavelength of 808 nm. The SVR is designed based on the linear birefringence of alpha-barium borate (alpha-BBO) crystal and fabricated using a dry etching process. Radially polarizedlight of high purity (> 96% at far-field distribution) was generated experimentally using the segmented SVR positioned between two quarter waveplates with orthogonal slow axes. The emergent polarization can be switched between radially and azimuthally polarized cylindrical vector beams with a pair of half-wave plates.

A self-mixing interferometry with mutual independent orthogonal polarizedlight is introduced. Its most important feature is that two mutual independent orthogonal lights are used as measuring and reference light. Frequency shifting and polarization multiplexing technologies are used in the proposed optical system. Phase variation of the two orthogonal polarizedbeams is simultaneously measured through heterodyne demodulation with a lock-in amplifier. The phase difference of the orthogonal polarizedlight accurately reflects the target displacement. The target in this system is a non-cooperative object which is different from a traditional Michelson interferometer. The primary experimental results show that this kind of self-mixing interferometry is very feasible. Under typical room conditions, the system's short-term resolution is better than 2 nm.

Full Text Available We present a new all-digital technique to extract the wavefront of a structured lightbeam. Our method employs non-homogeneous polarization optics together with dynamic, digital holograms written to a spatial light modulator to measure the phase...

This comprehensive introduction to polarizedlight provides students and researchers with the background and the specialized knowledge needed to fully utilize polarizedlight. It provides a basic introduction to the interaction of light with matter for those unfamiliar with photochemistry and photophysics. An in-depth discussion of polarizing optics is also given. Different analytical techniques are introduced and compared and introductions to the use of polarizedlight in various forms of spectroscopy are provided.Key Features* Starts at a basic level and develops tools for resear

This proposal requests support for the fabrication and operation of a modest facility that would provide relatively intense beams of monochromatic and polarized photons with energies in the range of several hundreds of MeV. These {gamma} rays would be produced by Compton backscattering laser light from the electrons circulating in the 2.5-3.0 GeV 'X-RAY' storage ring of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The excellent emittance, phase space, and high current of this state-of-the-art storage ring will allow the production of 2 x 10{sup 7} {gamma} rays per second. These photons would be tagged by detecting the scattered electrons, thereby determining the energy to 2.7 MeV for all {gamma}-ray energies. The efficiency of this tagging procedure is 100% and the {gamma}-ray beam would be essentially background free. Tagging will also allow the flexibility of operating with a dynamic range as large as 200 MeV in photon energy while still preserving high resolution and polarization. These beams will permit a fruitful study of important questions in medium-energy nuclear physics. The initial goals of this program are to reach reliable operation with photon energies up to 300 MeV and to develop {gamma}-ray beams with energies up to about 500 MeV. To demonstrate reliable operation, a modest physics program is planned that, for the most part, utilizes existing magnets and detector systems but nonetheless addresses several important outstanding problems. Gamma ray beams of the versatility, intensity, energy, and resolution that can be achieved at this facility are not currently available at any other world facility either existing or under construction. Furthermore, the proposed program would produce the first intense source of medium-energy {gamma} rays that are polarized. Because of the difficulties in producing such polarizedbeams, it is very unlikely that viable alternate sources can be developed in the near future; at

We have measured the polarization of neutrons produced from the reaction pd→n↘ at a laboratory angle of 20° at an incident proton kinetic energy of 800 MeV. For the highest energy neutron peak at ˜665 MeV, as well as for the broad pion production peak at ˜325 MeV, the neutron polarization has been found to be ˜0.20. The measured polarization for the quasielastic process has been found to be in good agreement with the free np analyzing power measurements. Such a polarized neutron beam, having a broad spectrum of momenta from 800 to 1300 MeV/c has been used at LAMPF for free np spin correlation measurements.

Polarizedlight microscopy provides unique opportunities for analyzing the molecular order in heterogeneous systems, such as living cells and tissues, without using exogenous dyes or labels. This article briefly discusses the theory of polarizedlight microscopy and elaborates on its practice using a traditional polarizedlight microscope and more specialized polarization microscopes such as the LC-PolScope, Oosight, or Abrio. The microscope components specific to analyzing the polarization of light, such as polarizer and compensator, are introduced, and quantitative techniques for measuring the birefringence of the specimen point by point using a traditional polarizing microscope are discussed. The new LC-PolScope greatly improves the analytic power of the technique, providing quantitative birefringence data simultaneously for every image point, thereby revealing molecular order with unprecedented sensitivity and at the highest resolution of the light microscope. Practical aspects discussed include the choice of optics, sample preparation, and combining polarizedlight with differential interference contrast and fluorescence microscopy. A glossary of polarization optical terms is also included to facilitate the discussion of observations made with a polarizedlight microscope.

Higher-order polarization singularities embedded in tailored vector beams are introduced and experimentally realized. As holographic modulation allows to define order and location of any vectorial singularity, the surrounding vector field can be dynamically shaped. We demonstrate light fields associated with flowers or spider webs due to regular and even irregular patterns of the orientation of polarization ellipses. Beyond that, not yet investigated hybrid structures are introduced that allow generating networks of flowers and webs in very close vicinity. Our results pave the way to applications of singular optics in spatially extended, optimized optical tweezing and high-resolution imaging.

Polarization measurement of orthogonal light scattering is introduced as a new optical parameter in flow cytometry. In the experimental setup, the electrical field of the incident laser beam is polarized in the direction of the sample flow. The intensity of the orthogonal light scattering polarized

Surface magnetism is studied by means of an ion beam of low energy (2-15 keV) scattered off the surface under grazing incidence conditions. During the scattering, a small fraction of the ions is neutralized into excited states which decay subsequently by light emission. The circular polarization of

RHIC has provided polarized proton collisions from 31 GeV to 255 GeV in the past decade. To preserve polarization through numerous depolarizing resonances through the whole accelerator chain, harmonic orbit correction, partial snakes, horizontal tune jump system and full snakes have been used. In addition, close attentions have been paid to betatron tune control, orbit control and beam line alignment. The polarization of 60% at 255 GeV has been delivered to experiments with 1.8×1011 bunch intensity. For the eRHIC era, the beam brightness has to be maintained to reach the desired luminosity. Since we only have one hadron ring in the eRHIC era, existing spin rotator and snakes can be converted to six snake configuration for one hadron ring. With properly arranged six snakes, the polarization can be maintained at 70% at 250 GeV. This paper summarizes the effort and plan to reach high polarization with small emittance for eRHIC.

The vector and tensor polarizations of a deuteron beam have been measured using elastic deuteron-carbon scattering at 75.6 MeV and deuteron-proton scattering at 270 MeV. After acceleration to 1170 MeV inside the COSY ring, the polarizations of the deuterons were checked by studying a variety of nuclear reactions using a cluster target at the ANKE magnet spectrometer placed at an internal target position of the storage ring. All these measurements were consistent with the absence of depolarization during acceleration and provide a number of secondary standards that can be used in subsequent experiments at the facility.

The various presented herein relate to an on-chip polarizationbeam splitter (PBS), which is adiabatic for the transverse magnetic (TM) mode and diabatic for the transverse electric (TE) mode. The PBS comprises a through waveguide and a cross waveguide, wherein an electromagnetic beam comprising TE mode and TM mode components is applied to an input port of the through waveguide. The PBS can be utilized to separate the TE mode component from the TM mode component, wherein the TE mode component exits the PBS via an output port of the through waveguide, and the TM mode component exits the PBS via an output port of the cross waveguide. The PBS has a structure that is tolerant to manufacturing variations and exhibits high polarization extinction ratios over a wide bandwidth.

The future medium energy physics program at the electron stretcher accelerator ELSA of Bonn University mainly relies on experiments using polarized electrons in the energy range from 1 to 3.2 GeV. To provide a polarizedbeam with high polarization and sufficient intensity a dedicated source has been developed and set into operation. To prevent depolarization during acceleration in the circular accelerators several depolarizing resonances have to be corrected for. Intrinsic resonances are compensated using two pulsed betatron tune jump quadrupoles. The influence of imperfection resonances is successfully reduced applying a dynamic closed orbit correction in combination with an empirical harmonic correction on the energy ramp. In order to minimize beam depolarization, both types of resonances and the correction techniques have been studied in detail. It turned out that the polarization in ELSA can be conserved up to 2.5 GeV and partially up to 3.2 GeV which is demonstrated by measurements using a Møller polarimeter installed in the external GDH1-beamline. .

Synchrotron radiation by a point charge is a familiar subject in classical electrodynamics. Perhaps less familiar are some quantum mechanical corrections to the classical results. Some of those quantum aspects of synchrotron radiation are described. One of the quantum effects leads to the expectation that electrons in a storage ring will polarize themselves to 92% - a surprisingly high value. A semi-classical derivation of the quantum effects is given. An effort has been made to minimize the need of using quantum mechanics. Results are put together to derive a final expression of beampolarization. Conditions under which the expected 92% polarization is destroyed are found and attributed to depolarization resonances. The various depolarization mechanisms are first illustrated by an idealized example and then systematically treated by a matrix formalism. It is shown that the strength of depolarization is specified by a key quantity called the spin chromaticity. Finally as an application of the obtained results, an estimate of the achievable level of beampolarization for two existing electron storage rings, SPEAR and PEP, is given.

We present an approach that enables complete control over the amplitude, phase and arbitrary polarization state on the Poincar\\'e sphere of an optical beam in a 4-f system with a spatial light modulator (SLM). The beams can be constructed from a coaxial superposition of x- and y-linearly polarizedlight, each carrying structured amplitude profile and phase distributions by using an amplitude-modulated mask imposed on the SLM. The amplitude, phase and polarization distribution of vector beams with four free parameters can be tailored independently and simultaneously by the SLM.

The International Linear Collider (ILC) is a proposed e+e- collider, focused on precision measurement of the Standard Model and new physics beyond. Polarizedbeams are a key element of the ILC physics program. The physics studies are accompanied by an extensive R&D program for the creation of the polarizedbeams and the measurement of their polarization. This contribution will review the advantages of using beampolarization and its technical aspects and realization, such as the creation of polarizedbeams and the measurement of the polarization.

Objective The objective of this study was to determine the potential benefits of polarizedlight colposcopy compared with standard colposcopy examinations in the evaluation of women with abnormal cervical cytology. Materials and Methods Polarized and standard colposcopy examinations were performed on 330 subjects. Respective images and biopsy annotations were obtained. Sensitivity and specificity; differences in the severity of cervical neoplasia; agreement of colposcopy impression, biopsy intent and biopsy site; and differences in the number of biopsies were determined using the ROC, Bowker’s test of symmetry, kappa statistic and paired t-test, respectively. Results The sensitivity and specificity for a lesion being seen with non-polarizedlight and polarizedlight colposcopy were 96.8% and 64.5%; and 96.8% and 64.9%, respectively. There was no statistically significant difference in the ROC of the lesion being seen between non-polarized (80.7) and polarized (80.9) colposcopy. Likewise, there was no statistically significant difference in the ROC of intent to biopsy between non-polarized (80.2) and polarized colposcopy (78.8). The agreement of cervical histopathology and colposcopy impression for non-polarized and polarized colposcopy were 0.986 and 0.952, respectively. There was no significant difference between non-polarized and polarized colposcopy in the mean number of lesions seen or number of sites intended to biopsy. Conclusions Polarizedlight colposcopy was not useful as an adjunct to conventional colposcopy in this study. Further research needs to be performed to determine the overall utility of polarizedlight colposcopy in clinical practice. PMID:25943867

We present both experimentally and theoretically the transformation of radially and azimuthally polarized vector beams when they propagate through a biaxial crystal and are transformed by the conical refraction phenomenon. We show that, at the focal plane, the transverse pattern is formed by a ring-like light structure with an azimuthal node, being this node found at diametrically opposite points of the ring for radial/azimuthal polarizations. We also prove that the state of polarization of the transformed beams is conical refraction-like, i.e. that every two diametrically opposite points of the light ring are linearly orthogonally polarized.

We describe a beam profile monitor design based on Cherenkov light emitted from a charged particle beam in an air gap. The main components of the profile monitor are silicon wafers used to reflect Cherenkov light onto a camera lens system. The design allows for measuring large beam sizes, with large photon yield per beam charge and excellent signal linearity with beam charge. The profile monitor signal is independent of the particle energy for ultrarelativistic particles. Different design and parameter considerations are discussed. A Cherenkov light-based profile monitor has been installed at the FACET User Facility at SLAC. We report on the measured performance of this profile monitor.

The objective of this study was to determine the potential benefits of polarizedlight colposcopy compared with standard colposcopy examinations in the evaluation of women with abnormal cervical cytology. Polarized and standard colposcopy examinations were performed on 330 subjects. Respective images and biopsy annotations were obtained. Sensitivity and specificity; differences in the severity of cervical neoplasia; agreement of colposcopy impression, biopsy intent, and biopsy site; and differences in the number of biopsies were determined using the ROC, Bowker's test of symmetry, kappa statistic, and paired t test, respectively. The sensitivity and specificity for a lesion being seen with nonpolarized light and polarizedlight colposcopy were 96.8% and 64.5%, and 96.8% and 64.9%, respectively. There was no statistically significant difference in the ROC of the lesion being seen between nonpolarized (80.7) and polarized (80.9) colposcopy. Likewise, there was no statistically significant difference in the ROC of intent to biopsy between nonpolarized (80.2) and polarized colposcopy (78.8). The agreement of cervical histopathology and colposcopy impression for nonpolarized and polarized colposcopy were 0.986 and 0.952, respectively. There was no significant difference between nonpolarized and polarized colposcopy in the mean number of lesions seen or number of sites intended to biopsy. Polarizedlight colposcopy was not useful as an adjunct to conventional colposcopy in this study. Further research needs to be performed to determine the overall utility of polarizedlight colposcopy in clinical practice.

Full Text Available A photonic crystal polarizationbeam splitter based on photonic band gap and self-collimation effects is designed for optical communication wavelengths. The photonic crystal structure consists of a polarization-insensitive self-collimation region and a splitting region. TM- and TE-polarized waves propagate without diffraction in the self-collimation region, whereas they split by 90 degrees in the splitting region. Efficiency of more than 75% for TM- and TE-polarizedlight is obtained for a polarizationbeam splitter size of only 17 μm x 17 μm in a wavelength interval of 60 nm including 1.55 μm.

Beamlet spot images are used to diagnose cross-beam energy transfer (CBET) during OMEGA direct-drive implosions. The spots are, in essence, the end point of beamlets of light originating from different regions of each beam profile and following paths determined by refraction. The intensity of each spot varies because of absorption and CBET along that path. When each beam is linearly polarized, the image is asymmetric in terms of spot intensities. A 3-D CBET postprocessor for hydrodynamics codes is used to model the intensity, wavelength, and polarization of light from each beam. Rotation of polarization caused by CBET is tracked. The model is benchmarked using a 3-D wave-based solver for simplified CBET geometries. For linearly polarizedbeams in OMEGA implosions, the model predicts that polarization effects will result in asymmetric polarization and unabsorbed light profiles that are different for each beam. An asymmetric beamlet spot image similar to that recorded is predicted by the CBET model for linearly polarizedbeams. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

An efficient polarizationbeam splitter (PBS) based on an optofluidic ring resonator (OFRR) is proposed and experimentally demonstrated. The PBS relies on the large effective refractive index difference between transverse-electric (TE) and transverse-magnetic (TM) polarization states, since the silica-microcapillary-based OFRR possesses a slab-like geometry configuration in the cross section through which the circulating light travels. To the best of our knowledge, this is the first OFRR-based PBS. In our work, the maximum polarization splitting ratio of up to 30 dB is achieved. Besides, water and ethanol are pumped into the core of the silica microcapillary respectively, and the maximum wavelength tuning range of 7.02 nm is realized when ethanol flows through the core, verifing the tuning principle of the PBS effectively. With such a good performance and simple scheme, this OFRR-based PBS is promising for applications such as tunable optical filters, demultiplexers, and routers.

In experiments in vitro on a man, cat and rat thrombocyte-free plasma it was determined that the polarizedlight over 5 cm distance from the object (6 min exposure) causes the inhibition of fibrinolytic activity of euglobulin fraction. It was shown that the fibrinolytic inhibition under the influence of the polarizedlight is connected with its antiplasmin effect. The importance of the fibrinolytic reaction for the course of inflammation process and tissue regeneration after injury and the role of therapy with polarizedlight in these reactions is discussed.

Preliminary analysis of polarized images of earth collected by hand-held cameras on Shuttle Missions 51A, 51G, 51I, and 61A indicate that information of the earth's surface and atmosphere exists in those data. To ensure that follow-on research in polarization is focused upon and that the experiments are properly designed to address specific questions, 26 scientists with past experience and interest in polarization observations met at the Lyndon B. Johnson Space Center on November 3 to 5, 1987. This conference report summarizes the discussions and provides the recommendations of the group for follow-on research.

Coherent vector beams with involved states of polarization (SOP) are widespread in the literature, having applications in laser processing, super-resolution imaging and particle trapping. We report novel vector beams obtained by transforming a Gaussian beam passing through a biaxial crystal, by means of the conical refraction phenomenon. We analyze both experimentally and theoretically the SOP of the different vector beams generated and demonstrate that the SOP of the input beam can be used to control both the shape and the SOP of the transformed beam. We also identify polarization singularities of such beams for the first time and demonstrate their control by the SOP of an input beam.

We present a new all-digital technique to extract the wavefront of a structured lightbeam. Our method employs non-homogeneous polarization optics together with dynamic, digital holograms written to a spatial light modulator to measure the phase relationship between orthogonal polarization states in real-time, thereby accessing the wavefront information. Importantly, we show how this can be applied to measuring the wavefront of propagating light fields, over extended distances, without any moving components. We illustrate the versatility of the tool by measuring propagating optical vortices, Bessel, Airy and speckle fields. The comparison of the extracted and programmed wavefronts yields excellent agreement.

is the strong nonparaxiality of the lightbeam, which contributes to the pulling force owing to momentum conservation. The nonparaxiality of the Bessel beam can be manipulated to possess a dragging force along both the radial longitudinal directions, i.e., a "tractor beam" with stable trajectories is achieved...

We demonstrate a type of chiral effect of an atomic medium. Polarization rotation of a probe beam is observed only when both a magnetic field and a linearly polarized coupling beam are present. We compare it with other chiral effects like optical activity, the Faraday effect, and the optically induced Faraday effect from the viewpoint of spatial inversion and time reversal transformations. As a theoretical model we consider a five-level configuration involving the cesium D2 transition. We use spin-polarized cold cesium atoms trapped in a magneto-optical trap to measure the polarization rotation versus probe detuning. The result shows reasonable agreement with a calculation from the master equation of the five-level configuration.

In order to improve the resolution of image scanning microscopy, we present a method based on image scanning microscopy and radially polarizedlight. According to the theory of image scanning microscopy, we get the effective point spread function of image scanning microscopy with the longitudinal component of radially polarizedlight and a 1 AU detection area, and obtain imaging results of the analyzed samples using this method. Results show that the resolution can be enhanced by 7% compared with that in image scanning microscopy with circularly polarizedlight, and is 1.54-fold higher than that in confocal microscopy with a pinhole of 1 AU. Additionally, the peak intensity of ISM is 1.54-fold higher than that of a confocal microscopy with a pinhole of 1 AU. In conclusion, the combination of the image scanning microscopy and the radially polarizedlight could improve the resolution, and it could realize high-resolution and high SNR imaging at the same time.

Free-space lightbeams with complex intensity patterns, or non-trivial phase structure, are demanded in diverse fields, ranging from classical and quantum optical communications, to manipulation and imaging of microparticles and cells. Static or dynamic spatial light modulators, acting on phase or intensity of an incoming light wave, are the conventional choices to produce beams with such non-trivial characteristics. However, interfacing these devices with optical fibers or integrated optical circuits often requires difficult alignment or cumbersome optical setups. Here we explore theoretically and with numerical simulations the potentialities of directly using the output of engineered three-dimensional waveguide arrays, illuminated with linearly polarizedlight, to project lightbeams with peculiar structures. We investigate through a collection of illustrative configurations the far field distribution, showing the possibility to achieve orbital angular momentum, or to produce elaborate intensity or phase pa...

Depth discrimination of polarizedlight is used in investigating laser Doppler measurement of the superficial microcirculation in tissue. Using polarization Monte Carlo simulation, temporal point spread function and power spectral distribution of backscattered polarization remaining light firstly are used to prove polarizedlight to be valid in measuring moving blood cell perfusion and mean flow velocity. Then simulation of layered medium model demonstrate that relationships between blood flow perfusion and mean frequency shift are linear to medium flowing velocity, and the Doppler shift information in polarization remaining light mainly comes from lower layer medium up to about 14 times of mean free path (MFP) of medium investigated and can be considered that Doppler effects come only from lower layer of the medium. Simulations in three-layer tissue model show that moving blood cell perfusion and mean blood cell moving velocity calculated from polarization remaining are much more sensitive to lower layer flow velocity variation, and more irrelevant to deeper layer flow rate fluctuations, that further confirms Doppler measurement from polarization remaining light to be effective for superficial microcirculation in tissue. Factors affecting Laser Doppler measurement like medium absorption, percentage of moving particles in blood detector size are discussed.

This is a single scene from a pair (frames 021 and 024) to study the effects of polarizedlight in Earth Observations. One scene was exposed with vertically polarizedlight, the other, horizontally. The subject in this study, is a lake behind Presa (dam) Don Martin (27.5N, 100.5W) on thge edge of the Rio Grande Plain near it's boundry with the Sierra Madre Oriental in Coahuila, Mexico.

This is a single scene from a pair (frames 021 and 024) to study the effects of polarizedlight in Earth Observations. One scene was exposed with vertically polarizedlight, the other, horizontally. The subject in this study, is a lake behind Presa (dam) Don Martin (27.5N, 100.5W) on thge edge of the Rio Grande Plain near it's boundry with the Sierra Madre Oriental in Coahuila, Mexico.

Semiconductor nanorods have anisotropic absorption and emission properties. In this work a hybrid luminescent layer is produced based on a mixture of CdSe/CdS nanorods dispersed in a liquid crystal that is aligned by an electric field and polymerized by UV illumination. The film emits light with polarization ratio 0.6 (polarization contrast 4:1). Clusters of nanorods in liquid crystal can be avoided by applying an AC electric field with sufficient amplitude. This method can be made compatible with large-scale processing on flexible transparent substrates. Thin polarizedlight emitters can be used in LCD backlights or solar concentrators to increase the efficiency.

Full Text Available Semiconductor nanorods have anisotropic absorption and emission properties. In this work a hybrid luminescent layer is produced based on a mixture of CdSe/CdS nanorods dispersed in a liquid crystal that is aligned by an electric field and polymerized by UV illumination. The film emits light with polarization ratio 0.6 (polarization contrast 4:1. Clusters of nanorods in liquid crystal can be avoided by applying an AC electric field with sufficient amplitude. This method can be made compatible with large-scale processing on flexible transparent substrates. Thin polarizedlight emitters can be used in LCD backlights or solar concentrators to increase the efficiency.

A composite optical structure consisting of two quarter-wave plates and a single half-wave plate is proposed for compensating for the polarization distortion induced by a non-ideal beam splitter in a Michelson interferometer. In the proposed approach, the optimal orientations of the optical components within the polarization compensator are determined using a genetic algorithm (GA) such that the beam splitter can be treated as a free-space medium and modeled using a unit Mueller matrix accordingly. Two implementations of the proposed polarization controller are presented. In the first case, the compensator is placed in the output arm of Michelson interferometer such that the state of polarization of the interfered output light is equal to that of the input light. However, in this configuration, the polarization effects induced by the beam splitter in the two arms of the interferometer structure cannot be separately addressed. Consequently, in the second case, compensator structures are placed in the Michelson interferometer for compensation on both the scanning and reference beams. The practical feasibility of the proposed approach is introduced by considering a Mueller polarization-sensitive (PS) optical coherence tomography (OCT) structure with three polarization controllers in the input, reference and sample arms, respectively. In general, the results presented in this study show that the proposed polarization controller provides an effective and experimentally-straightforward means of compensating for the polarization distortion effects induced by the non-ideal beam splitters in Michelson interferometers and Mueller PS-OCT structures.

We experimentally measured the self-healing of the spatially inhomogeneous states of polarization of radial and azimuthal polarized vector Bessel beams. Radial and azimuthal polarized vector Bessel beams were generated via a digital version of Durnin's method, using a spatial light modulator in concert with a liquid crystal $q$-plate. As a proof of principle, their intensities and spatially inhomogeneous states of polarization were measured using Stokes polarimetry as they propagated through two disparate obstructions. It was found, similar to their intensities, the spatially inhomogeneous states of polarization of a radial and azimuthal polarized vector Bessel beams self-heal. Similar to scalar Bessel beams, the self-healing of vector Bessel beams can be understood via geometric optics, i.e., the interference of the unobstructed conical rays in the shadow region of the obstruction. The self-healing of vector Bessel beams may have applications in, for example, optical trapping.

Random LightBeams: Theory and Applications contemplates the potential in harnessing random light. This book discusses light matter interactions, and concentrates on the various phenomena associated with beam-like fields. It explores natural and man-made light fields and gives an overview of recently introduced families of random lightbeams. It outlines mathematical tools for analysis, suggests schemes for realization, and discusses possible applications. The book introduces the essential concepts needed for a deeper understanding of the subject, discusses various classes of deterministic par

We discuss polarizing a proton beam in a storage ring, either by selective removal or by spin flip of the stored ions. Prompted by recent, conflicting calculations, we have carried out a measurement of the spin flip cross section in low-energy electron-proton scattering. The experiment uses the cooling electron beam at COSY as an electron target. The measured cross sections are too small for making spin flip a viable tool in polarizing a stored beam. This invalidates a recent proposal to use co-moving polarized positrons to polarize a stored antiproton beam.

We demonstrate a convenient approach for simultaneously manipulating the amplitude and polarization of lightbeams by means of the modulation of the correlation structure. As an illustration, an arbitrary radially polarized array (RPA) beam of a radial or rectangular symmetry array is obtained by focusing a conventional radially polarizedbeam with specially designed correlation structure. The physical realizability conditions for such source and the far-field beam condition are derived. It is illustrated that the far-field beamlet shape and the state of polarization are strictly controlled by the initial correlation structure and the correlation parameter. Furthermore, by designing the source correlation structure, a tunable OK-shaped RPA beam and an optical cage are demonstrated, which can find widespread applications in micro-nano engineering and non-destructive manipulation of living biological cells.

We demonstrate a convenient approach for simultaneously manipulating the amplitude and polarization of lightbeams by means of the modulation of the correlation structure. As an illustration, we constructed a periodic correlation structure that can generate an arbitrary radially polarized array (RPA) beam of a radial or rectangular symmetry array in the focal plane from a radially polarized (RP) beam. The physical realizability conditions for such source and the far-field beam condition are derived. It is illustrated that the beamlet shape and the state of polarization (SOP) can be effectively controlled by the initial correlation structure and the coherence width. Furthermore, by designing the source correlation structure, a tunable OK-shaped RPA beam and an optical cage are demonstrated, which can find widespread applications in non-destructive manipulation of particles and living biological cells. The arbitrariness in the design of correlation structure prompted us to find more convenient approaches for co...

Recently, many methods based on amplitude or phase modulation to reduce the focal spot and enhance the longitudinal field component of a tight-focused radially polarizedlightbeam have been suggested. But they all suffer from spot size limit 0.36λ/NA and large side lobes strength in longitudinal component. Here, we report a method of generating a tighter focused spot by focusing radially polarized and azimuthally polarizedbeams of different wavelengths on a thin photochromic film through a high-numerical-aperture lens simultaneously. In this method, by suppressing the radial component and compressing the longitudinal component of radially polarizedbeam, absorbance modulation makes the ultimate spot size break the size limit of 0.36λ/NA with side-lobe intensity of longitudinal component below 1% of central-peak intensity. The theoretical analysis and simulation demonstrate that the focal spot size could be smaller than 0.1λ with nearly all radial component blocked at high intensity ratio of the two illuminating beams.

Conventional caustic methods in real or Fourier space produced accelerating optical beams only with convex trajectories. We develop a superposition caustic method capable of winding lightbeams along non-convex trajectories. We ascertain this method by constructing a one-dimensional (1D) accelerating beam moving along a sinusoidal trajectory, and subsequently extending to two-dimensional (2D) accelerating beams along arbitrarily elliptical helical trajectories. We experimentally implement the method with a compact and robust integrated optics approach by fabricating micro-optical structures on quartz glass plates to perform the spatial phase and amplitude modulation to the incident light, generating beam trajectories highly consistent with prediction. The theoretical and implementation methods can in principle be extended to the construction of accelerating beams with a wide variety of non-convex trajectories, thereby opening up a new route of manipulating lightbeams for fundamental research and practical ap...

Two-dimensional metasurface structures have recently been proposed to reduce the challenges of fabrication of traditional plasmonic metamaterials. However, complex designs and sophisticated fabrication procedures are still required. Here, we present a unique one-dimensional (1-D) metasurface based on bilayered metallic nanowire gratings, which behaves as an ideal polarizedbeam splitter, producing strong negative reflection for transverse-magnetic (TM) light and efficient reflection for transverse-electric (TE) light. The large anisotropy resulting from this TE-metal-like/TM-dielectric-like feature can be explained by the dispersion curve based on the Bloch theory of periodic metal-insulator-metal waveguides. The results indicate that this photon manipulation mechanism is fundamentally different from those previously proposed for 2-D or 3-D metastructures. Based on this new material platform, a novel form of metasurface holography is proposed and demonstrated, in which an image can only be reconstructed by using a TM lightbeam. By reducing the metamaterial structures to 1-D, our metasurface beam splitter exhibits the qualities of cost-efficient fabrication, robust performance, and high tunability, in addition to its applicability over a wide range of working wavelengths and incident angles. This development paves a foundation for metasurface structure designs towards practical metamaterial applications.

The light scattering properties of leaves are used as input data for models which mathematically describe the transport of photons within plant canopies. Polarization measurements may aid in the investigation of these properties. This paper describes an instrument for rapidly determining the bidirectional light scattering properties of leaves illuminated by linearly polarizedlight. Results for one species, magnolia, show large differences in the bidirectional light scattering properties depending whether or not the electric vector E is parallel to the foliage surface.

Experimental directions which will be the most useful in developing underlying theories of hadronic collisions are outlined. As a pedagogical device to accomplish this, approximate percentages of a total program which could be devoted to different areas have been quoted. Findings are presented in the form of a short basic report with several long detailed appendices. In the basic report our opinion as to the amount of polarizedbeam experimental effort that should be applied to the following areas is stated: nucleon-nucleon scattering, quasi-two-body processes, inclusive production, and new or unexplored areas (such as large p/sub T/ and invariance principles). Our reasoning is discussed briefly, however, the details are left for the appendices. Members of the panel present certain aspects of the above areas, which should be useful for planning and/or performing polarizedbeam experiments. The seven presentations are abstracted separately in ERA.

@@ We investigate coherent beam combination of fibre laser beams by phase locking. Phase noise of a polarization maintaining ytterbium fibre amplifier is inspected with a fibre interferometer. In a feed back control loop, two fibre polarization maintaining ytterbium amplifiers are phase locked and coherent combined when the phase noise is properly controlled by a LiNO3 phase modulator.

The possibility of focusing light to an ever tighter spot has important implications for many applications and fields of optics research, such as nano-optics and plasmonics, laser-scanning microscopy, optical data storage and many more. The size of lateral features of the field at the focus depends on several parameters, including the numerical aperture of the focusing system, but also the wavelength and polarization, phase and intensity distribution of the input beam. Here, we study the smallest achievable focal feature sizes of coherent superpositions of two co-propagating beams carrying opposite orbital angular momentum. We investigate the feature sizes for this class of beams not only in the scalar limit, but also use a fully vectorial treatment to discuss the case of tight focusing. Both our numerical simulations and our experimental results confirm that lateral feature sizes considerably smaller than those of a tightly focused Gaussian lightbeam can be observed. These findings may pave the way for impr...

Free-space lightbeams with complex intensity patterns, or non-trivial phase structure, are demanded in diverse fields, ranging from classical and quantum optical communications, to manipulation and imaging of microparticles and cells. Static or dynamic spatial light modulators, acting on the phase or intensity of an incoming light wave, are the conventional choices to produce beams with such non-trivial characteristics. However, interfacing these devices with optical fibers or integrated optical circuits often requires difficult alignment or cumbersome optical setups. Here we explore theoretically and with numerical simulations the potentialities of directly using the output of engineered three-dimensional waveguide arrays, illuminated with linearly polarizedlight, to project lightbeams with peculiar structures. We investigate through a collection of illustrative configurations the far field distribution, showing the possibility to achieve orbital angular momentum, or to produce elaborate intensity or phase patterns with several singularity points. We also simulate the propagation of the projected beam, showing the possibility to concentrate light. We note that these devices should be at reach of current technology, thus perspectives are open for the generation of complex free-space optical beams from integrated waveguide circuits.

Non-symmetric and directional reflectivity from three dimensional (3D) laser induced periodic surface structures (LIPSS) is considered. LIPSS structures were patterned in stainless steel (W720) by using linear and elliptical polarized laser beams from a femtosecond (fs) laser. The short and long periodic ripples and possible other type artifact remaining has decreasing influences to relative reflectivity variation between 5% and 65% in the wavelength range from 200nm to 800nm. The studies of patterned W720LIPSS structures indicated, besides of increased surface area, that decrease of reflectivity is affected by light scattering from ultra-structures of LIPSS and produces resonance type differences in spectral reflectivity when either TM or TE polarized probing beam interacts with micro- and ultrastructure of LIPSS.

A tunable dichroic polarizationbeam splitter (tunable DPBS) simultaneously performs the follow functions: 1. Separation of a polarized incident beam into multiple pairs of orthogonally polarizedbeams; 2. Separation of the propagation direction of two wavelength incident beams after passing through the tunable DPBS; and 3. Control of both advanced polarization and wavelength separation capabilities by varying the temperature of the tunable DPBS. This novel complex optical property is realized by diffraction phenomena using a designed three-dimensional periodic structure of aligned liquid crystals in the tunable DPBS, which was fabricated quickly with precision in a one-step photoalignment using four-beampolarization interferometry. In experiments, we demonstrated that these diffraction properties are obtained by entering polarizedbeams of wavelengths 532 nm and 633 nm onto the tunable DPBS. These diffraction properties are described using the Jones calculus in a polarization propagation analysis. Of significance is that the aligned liquid crystal structure needed to obtain these diffraction properties was proposed based on a theoretical analysis, and these properties were then demonstrated experimentally. The tunable DPBS can perform several functions of a number of optical elements such as wave plates, polarizationbeam splitter, dichroic beam splitter, and tunable wavelength filter. Therefore, the tunable DPBS can contribute to greater miniaturization, sophistication, and cost reduction of optical systems used widely in applications, such as optical measurements, communications, and information processing.

Full Text Available We are presenting an experimental setup based on polarizedlight, enabling the visualization of the magnetic field of magnetic assemblies using a Hele-Shaw cell filled with ferrofluids. We have simulated the observed patterns with hypergeometric polynomials.

Originally an empirical law, nowadays Malus' is seen as a key experiment to demonstrate the traversal nature of electromagnetic waves, as well as the intrinsic connection between optics and electromagnetism. More specifically, it is an operational way to characterize a linear polarized electromagnetic wave. A simple and inexpensive setup is proposed in this work, to quantitatively verify the nature of polarizedlight. A flat computer screen serves as a source of linear polarizedlight and a smartphone is used as a measuring instrument thanks to its built-in sensors. The intensity of light is measured by means of the luminosity sensor with a tiny filter attached over it. The angle between the plane of polarization of the source and the filter is measured by means of the three-axis accelerometer, that works, in this case, as an inclinometer. Taken advantage of the simultaneous use of these two sensors, a complete set of measures can be obtained just in a few seconds. The experimental light intensity as a functi...

The main subject of this contribution is the all-optical control over the state of polarization (SOP) of light, understood as the control over the SOP of a signal beam by the SOP of a pump beam. We will show how the possibility of such control arises naturally from a vectorial study of pump-probe Raman interactions in optical fibers. Most studies on the Raman effect in optical fibers assume a scalar model, which is only valid for high-PMD fibers (here, PMD stands for the polarization-mode dispersion). Modern technology enables manufacturing of low-PMD fibers, the description of which requires a full vectorial model. Within this model we gain full control over the SOP of the signal beam. In particular we show how the signal SOP is pulled towards and trapped by the pump SOP. The isotropic symmetry of the fiber is broken by the presence of the polarized pump. This trapping effect is used in experiments for the design of new nonlinear optical devices named Raman polarizers. Along with the property of improved sig...

Generation of spatially inhomogeneously polarized (SIP) beams due to polarization spatial mode nonseparability is demonstrated using a polarization Sagnac interferometer. Counter propagating horizontal (H) and vertical (V) polarized Laguerre Gaussian beams of opposite topological charges(LG01)corresponding to the two binary degrees of freedom (DoF) are coherently superposed in the interferometer. Quantum inspired entanglement witness and quantification such as Bell state measurement, violation of CHSH form of Bells inequality and concurrence measurements are experimentally measured to establish nonseparability between the two DoF. As the SIP beams are equivalent to bipartite pure states, point wise Stokes polarimetry measurements are used to calculate the reduced coherency matrix corresponding to polarization DoF. Using these we calculate the linear entropy and maximized Bells measure to quantify the degree of entanglement of the SIP beams.

The theoretical and experimental results of tightly focused radially polarized vortex beams are demonstrated.An auto-focus technology is introduced into the measurement system in order to enhance the measurement precision,and the radially polarized vortex beams are generated by a liquid-crystal polarization converter and a vortex phase plate.The focused fields of radially polarized vortex beams with different topological charges at numerical apertures (NAs) of 0.65 and 0.85 are measured respectively,and the results indicate that the total intensity distribution at focus is dependent not only on the NA of the focusing objective lens and polarization pattem of the beam but also on the topological charge l of the beam.Some unique focusing properties of radially polarized vortex beams with fractional topological charges are presented based on numerical calculations.The experimental verification paves the way for some practical applications of radially polarized vortex beams,such as in optical trapping,near-field microscopy,and material processing.

A 28 keV beam of 31Mg+ ions was extracted from a uranium carbide, proton-beam-irradiated target coupled to a laser ion source. The ion beam was nuclear-spin polarized by collinear optical pumping on the 2it {S}_{1/2}-2it {P}_{1/2} transition at 280 nm. The polarization was preserved by an extended 1 mT guide field as the beam was transported via electrostatic bends into a 2.5 T longitudinal magnetic field. There the beam was implanted into a single crystal MgO target and the beta decay asymmetry was measured. Both hyperfine ground states were optically pumped with a single frequency light source, using segmentation of the beam energy, which boosted the polarization by approximately 50 % compared to pumping a single ground state. The total decay asymmetry of 0.06 and beam intensity were sufficient to provide a useful spin-1/2 beam for future BNMR experiments. A variant of the method was used previously to optically pump the full Doppler-broadened absorption profile of a beam of 11Be+ with a single-frequency light source.

@@ A metal wire nanograting is fabricated and used as a polarizingbeam splitter that reflects TE polarization and transmits TM polarization. The metal wire nanograting is based on a fully optimized design structure that consists of not only the core nanowire metal grid but also the substrate nanograting. The substrate nanograting is designed to provide better performance for both TM and TE polarizations. We fabricate metal-stripe gratings on a glass substrate using nanoimprint lithography and reactive ion etching process. A detailed investigation of the polarization effect at 1550 nm wavelength is carried out with the theoretical analysis and experimental results.The polarizingbeam splitter has uniform performance with wide variations in the incident angle (±25) and has high efficiency for both the reflected and the transmitted beams.

We have numerically and analytically shown that polarization singularities can emerge when a homogeneously elliptically polarizedlightbeam undergoes self-focusing in an isotropic third-order Kerr medium without frequency and spatial dispersion (fused silica, liquids, gases etc.) In the case of axially symmetric beam the emerging C-lines have the shape of circumference with the center at the beam's axis and they are located in the separate transversal planes in the medium. If the axial symmetry of the incident beam is broken then the even number of C-points with opposite topological charges are nucleated in the medium. They exist in a certain propagation coordinate range and then they collide and annihilate each other.

The concept of magnetic nanoprobes (or magnetic nanoantennas) providing a magnetic near-field enhancement and vanishing electric field is presented and investigated, together with their excitation. It is established that a particular type of cylindrical vector beams called azimuthally electric polarized vector beams yield strong longitudinal magnetic field on the beam axis where the electric field is ideally null. These beams with an electric polarization vortex and cylindrical symmetry are important in generating high magnetic to electric field contrast, i.e., large local field admittance, and in allowing selective excitation of magnetic transitions in matter located on the beam axis. We demonstrate that azimuthally polarized vector beam excitation of a photoinduced magnetic nanoprobe made of a magnetically polarizable nano cluster leads to enhanced magnetic near field with resolution beyond diffraction limit. We introduce two figures of merit as magnetic field enhancement and local field admittance normaliz...

We will explore the physics and technology of interaction of light (coherent and incoherent) with charged particle beams with the generation of novel types of electromagnetic radiation and particle sources in mind. Various configurations will be presented: incoherent scattering of coherent light (laser) from an incoherent particle beam (high temperature), coherent scattering of coherent light (laser) from a `cold' (bunched) beam, amplification of light by a particle beam, femtosecond generation of particle and lightbeams via `optical slicing' and Thomson/Compton scattering techniques, etc. We will explore the domains of untrashort temporal duration (femtoseconds) as well as of ultrashort wavelengths (x-rays and shorter), with varying degrees of coherence. The relevance of such sources to a few critical areas of research in the natural sciences e.g. ultrafast material, chemical and biological processes, protein folding, x-ray holography, particle phase space cooling and quantum computing will be briefly touched upon. All the processes discussed involve proper interpretation and understanding of coherent states of matter and radiation, as well as the quality and quantity of information and energy embedded in them.

The article presents layout of experiments for observatiion of polarizing effects on light passage through crossed polarizers. Addition of the third polarizer leads to appearance of light on the screen. Experiment is for cases with a laser light source, reflection of light under the Brewster's angle. Photos of the installations realizing the given effects are resulted.

POLAR is a compact polarimeter dedicated to measuring the polarization of GRBs between 50-350 keV.The light collection of 200 mm×6 mm×6 mm plastic bars has been simulated and optimized in order to get uniform response to X-rays at different points along one single bar.According to the Monte Carlo results,the amplitude uniformity strongly depends on the level of polishing of the scintillator surface and the covering.A uniformity of 89% is achieved with a prototype constructed by a non position-sensitive PMT and an array of 4×4 bars.

We report on a chiral nanostructure, which we term a "butterfly nanoantenna," that, when used in a metasurface, allows the direct conversion of a linearly polarizedbeam into a nonlinear optical far-field of arbitrary complexity. The butterfly nanoantenna exhibits field enhancement in its gap for every incident linear polarization, which can be exploited to drive nonlinear optical emitters within the gap, for the structuring of light within a frequency range not accessible by linear plasmonics. As the polarization, phase and amplitude of the field in the gap are highly controlled, nonlinear emitters within the gap behave as an idealized Huygens source. A general framework is thereby proposed wherein the butterfly nanoantennas can be arranged on a surface to produce a highly structured far-field nonlinear optical beam with high purity. A third harmonic Laguerre-Gauss beam carrying an optical orbital angular momentum of 41 is demonstrated as an example, through large-scale simulations on a high-performance comp...

We experimentally studied plasmon-polariton-assisted light propagation in serially coupled silver nanowire (Ag-NW) dimers and probed their dependence on bending-angle between the nanowires and polarization of incident light. From the angle-dependence study, we observed that obtuse angles between the nanowires resulted in better transmission than acute angles. From the polarization studies, we inferred that light emission from junction and distal ends of Ag-NW dimers can be systematically controlled. Further, we applied this property to show light routing and polarizationbeam splitting in obtuse-angled Ag-NW dimer. The studied geometry can be an excellent test-bed for plasmonic circuitry.

With the idea of the beaming models, we derive a relation between the observed polarization and Dopplercorrected magnitude; that is, the observed polarization is in anti-correlation with the Doppler-corrected magnitude. Making use of the infrared data observed simultaneously by Impey et al. [Mon. Not. R. Astron. Soc.200 (1982) 19; 209 (1984) 245] and Holmes et al. [ibid. 210 (1984) 961] we found that: (1) there is a significant correlation between the observed maximum polarization and Doppler-corrected magnitude but the polarization is not in anti-correlation with the Doppler-corrected magnitude; (2) the maximum infrared polarization is strongly correlated with the maximum optical polarization. Our conclusion is that the infrared polarization depends only on the degree of ordering of the magnetic field in the synchrotron emission regions and not on the beaming effect.Both infrared and optical emissions originate from the synchrotron radiation.

The multipartite polarization entangled states of bright optical beams directly associating with the spin states of atomic ensembles are one of the essential resources in the future quantum information networks, which can be conveniently utilized to transfer and convert quantum states across a network composed of many atomic nodes. In this letter, we present the experimental demonstration of tripartite polarization entanglement described by Stokes operators of optical field. The tripartite entangled states of light at the frequency resonant with D1 line of Rubidium atoms are transformed into the continuous variable polarization entanglement among three bright optical beams via an optical beam splitter network. The obtained entanglement is confirmed by the extended criterion for polarization entanglement of multipartite quantized optical modes.

We show that standard tissue phantoms can be used to mimic the intensity and polarization properties of tissue. Polarizedlight propagation through biologic tissue is typically studied using tissue phantoms consisting of dilute aqueous suspensions of microspheres. The dilute phantoms can empirically match tissue polarization and intensity properties. One discrepancy between the dilute phantoms and tissue exist: common tissue phantoms, such as dilute Intralipid and dilute 1-{micro}m-diameter polystyrene microsphere suspensions, depolarize linearly polarizedlight more quickly than circularly polarizedlight. In dense tissue, however, where scatterers are often located in close proximity to one another, circularly polarizedlight is depolarized similar to or more quickly than linearly polarizedlight. We also demonstrate that polarizedlight propagates differently in dilute versus densely packed microsphere suspensions, which may account for the differences seen between polarizedlight propagation in common dilute tissue phantoms versus dense biologic tissue.

Vector beams, which have space-variant state of polarization (SOP) comparing with scalar beams with spatially homogeneous SOP, are used to manipulate surface plasmon polarizations (SPPs). We find that the excitation, orientation, and distribution of the focused SPPs excited in a high numerical apert

We describe a beam splitter for polar neutral molecules. An electrostatic hexapole initially confines and guides a supersonic expansion of ammonia, and it then smoothly transforms into two bent quadrupole guides, thus splitting the molecular beam in two correlated fractions. This paves the way towards molecular beam experiments wherein one beam is modified through interactions with, e.g. a laser beam or another molecular beam, while the other one remains unmodified and serves as a reference. Because both beams originate from the same parent beam, such differential experiments can dramatically enhance the sensitivity. The highly complex electrode structure required for the beam splitter would be very difficult to build by traditional means. Instead, we introduce a new method of production: 3D printing of a plastic piece, followed by electroplating. The 3D printed piece can take any desired shape and, since the entire structure can be printed as a single piece, provides inherently precise alignment. Electroplat...

Beams with polarization singularities have attracted immense recent attention in a wide array of scientific and technological disciplines. We demonstrate a class of optical fibers in which these beams can be generated and propagated over long lengths with unprecedented stability, even in the pres......Beams with polarization singularities have attracted immense recent attention in a wide array of scientific and technological disciplines. We demonstrate a class of optical fibers in which these beams can be generated and propagated over long lengths with unprecedented stability, even...... in the presence of strong bend perturbations. This opens the door to exploiting nonlinear fiber optics to manipulate such beams. This fiber also possesses the intriguingly counterintuitive property of being polarization maintaining despite being strictly cylindrically symmetric, a prospect hitherto considered...... infeasible with optical fibers. (C) 2009 Optical Society of America....

The present thesis discusses the extraction of the electron-proton spin-flip cross-section. The experimental setup, the data analysis and the results are pictured in detail. The proton is described by a QCD-based parton model. In leading twist three functions are needed. The quark distribution, the helicity distribution and the transversity distribution. While the first two are well-known, the transversity distribution is largely unknown. A self-sufficient measurement of the transversity is possible in double polarized proton-antiproton scattering. This rises the need of a polarized antiproton beam. So far spin filtering is the only tested method to produce a polarized proton beam, which may be capable to hold also for antiprotons. In-situ polarization build-up of a stored beam either by selective removal or by spin-flip of a spin-(1)/(2) beam is mathematically described. A high spin-flip cross-section would create an effective method to produce a polarized antiproton beam by polarized positrons. Prompted by conflicting calculations, a measurement of the spin-flip cross-section in low-energy electron-proton scattering was carried out. This experiment uses the electron beam of the electron cooler at COSY as an electron target. The depolarization of the stored proton beam is detected. An overview of the experiment is followed by detailed descriptions of the cycle setup, of the electron target and the ANKE silicon tracking telescopes acting as a beam polarimeter. Elastic protondeuteron scattering is the analyzing reaction. The event selection is depicted and the beampolarization is calculated. Upper limits of the two electron-proton spin-flip cross-sections {sigma} {sub parallel} and {sigma} {sub perpendicular} {sub to} are deduced using the likelihood method. (orig.)

The LCD screen of a laptop computer provides a broad, bright, and extended source of polarizedlight. A number of demonstrations on the properties of polarizedlight from a laptop computer screens are presented here.

Polarizedlight technique clearly defines the fatigue zones in metal for measuring and photographing. White light is passed through a vertical polarizing filter and then is reflected onto the surface of the fracture specimen.

The LCD screen of a laptop computer provides a broad, bright, and extended source of polarizedlight. A number of demonstrations on the properties of polarizedlight from a laptop computer screens are presented here.

The present paper reports on the actual status of the theoretical concepts for the production of polarized heavy ion beams in storage rings and for methods to control online the degree of polarization as well as investigations of the preservation of the polarization during the ion movement across the magnetic system of the ring. It is argued that for hydrogen-like ions beampolarization can be built up efficiently by optical pumping of the Zeeman sublevels of ground-state hyperfine levels and that the maximal achievable nuclear polarization exceeds 90%. Of special interest are polarized helium-like ions which can be produced by the capture of one electron, because in selected cases parity nonconservation effects are found to be of unprecedented size in Atomic Physics. The measurements of these effects require online-diagnostics of the degree of the ion beampolarization. It is shown that this can be accomplished by an online-detection of the linear polarization of the X-rays which are emitted with the capture of the electron. In order to investigate the preservation of the polarization of the ions stored in the ring, the concept of an instantaneous quantization axis is introduced. The dynamics of this axis and the behaviour of the polarization with respect to it are explored in detail. (orig.)

The present paper reports on the actual status of the theoretical concepts for the production of polarized heavy ion beams in storage rings and for methods to control online the degree of polarization as well as investigations of the preservation of the polarization during the ion movement across the magnetic system of the ring. It is argued that for hydrogen-like ions beampolarization can be built up efficiently by optical pumping of the Zeeman sublevels of ground-state hyperfine levels and that the maximal achievable nuclear polarization exceeds 90%. Of special interest are polarized helium-like ions which can be produced by the capture of one electron, because in selected cases parity nonconservation effects are found to be of unprecedented size in Atomic Physics. The measurements of these effects require online-diagnostics of the degree of the ion beampolarization. It is shown that this can be accomplished by an online-detection of the linear polarization of the X-rays which are emitted with the capture of the electron. In order to investigate the preservation of the polarization of the ions stored in the ring, the concept of an instantaneous quantization axis is introduced. The dynamics of this axis and the behaviour of the polarization with respect to it are explored in detail. (orig.)

A linearly polarized photon beam has been produced at MAX-lab using the coherent bremsstrahlung of electrons with an energy of 192.6 MeV in a 0.1 mm thick diamond crystal. The intensity and shape of the coherent maxima and their dependence on the crystal orientation are similar to the features observed at higher electron energies (∼ 1 GeV) and are well described by coherent bremsstrahlung theory. The linear polarization of the uncollimated beam at the coherent peak energy ≈50–60 MeV is about 20% and can be increased to 40–45% if collimation of half the characteristic angle is used. At present the degree of polarization is high enough to allow the study of polarization observables in photo-nuclear reactions at MAX-lab in the energy range from Giant Dipole Resonance up to ≈80 MeV. -- Highlights: •A linearly polarized tagged photon beam has been produced at the MAX-lab facility. •The coherent bremsstrahlung spectra were measured for various crystal orientations. •The measured spectra are well described by the coherent bremsstrahlung theory. •The photon beampolarization can reach 50% at the Giant Resonance region. •Polarizedbeam provides performing nuclear experiments in the energy range 10–90 MeV.

Recently, a cryptosystem based on the analysis of light in the focal area of a high numerical aperture system has been proposed. A key element in the design of this device is the selection of the polarization of the input beam. In this paper we analyze how polarization influences the performance of the encoded message. In order to avoid attacks and enhance security, the system is assumed to work in photon-counting illumination conditions.

Sixty-six papers are presented as a report on conference sessions held from August 23-27, 1976, at Argonne National Laboratory. Topics covered include: (1) strong interactions; (2) weak and electromagnetic interactions; (3) polarizedbeams; and (4) polarized targets. A separate abstract was prepared for each paper for ERDA Energy Research Abstracts (ERA) and for the INIS Atomindex. (PMA)

polarizedlight in such a medium. The model is generalizable to any medium where polarization extinction and absolute attenuation of light can be measured...navigation in a nocturnal rainforest bee, Megalopta genalis. Our part of the work involved quantitating patterns and spectral properties of polarizedlight in

The PAX Collaboration has successfully performed a spin-filtering experiment with protons at the COSY-ring. The measurement allowed the determination of the spin-dependent polarizing cross section, that compares well with the theoretical prediction from the nucleon-nucleon potential. The test confirms that spin-filtering can be adopted as a method to polarize a stored beam and that the present interpretation of the mechanism in terms of the proton-proton interaction is correct. The outcome of the experiment is of utmost importance in view of the possible application of the method to polarize a beam of stored antiprotons.

Utilizing the inverse design engineering method of topology optimization, we have realized high-performing all-silicon ultra-compact polarizationbeam splitters. We show that the device footprint of the polarizationbeam splitter can be as compact as similar to 2 µm2 while performing experimentally...... with a polarization splitting loss lower than similar to 0.82 dB and an extinction ratio larger than similar to 15 dB in the C-band. We investigate the device performance as a function of the device length and find a lower length above which the performance only increases incrementally. Imposing a minimum feature...

We present the first experimental evidence of anisotropic photosensitivity of an isotropic homogeneous medium under uniform illumination. Our experiments reveal fundamentally new type of light induced anisotropy originated from the hidden asymmetry of pulsed lightbeam with a finite tilt of intensity front. We anticipate that the observed phenomenon, which enables employing mutual orientation of a lightpolarization plane and pulse front tilt to control interaction of matter with ultrashort light pulses, will open new opportunities in material processing.

This study proposes a slim planar apparatus for converting nonpolarized light from a light-emitting diode (LED) into an ultra-collimated linearly polarizedbeam uniformly emitted from its top surface. The apparatus was designed based on a folded-bilayer configuration comprising a light-mixing collimation element, polarization conversion element, and polarization-preserving light guide plate (PPLGP) with an overall thickness of 5 mm. Moreover, the apparatus can be extended transversally by connecting multiple light-mixing collimation elements and polarization conversion elements in a side-by-side configuration to share a considerably wider PPLGP, so the apparatus can have theoretically unlimited width. The simulation results indicate that the proposed apparatus is feasible for the maximal backlight modules in 39-inch liquid crystal panels. In the case of an apparatus with a 480 × 80 mm emission area and two 8-lumen LED light sources, the average head-on polarized luminance and spatial uniformity over the emission area was 5000 nit and 83%, respectively; the vertical and transverse angular distributions of the emitting light were only 5° and 10°, respectively. Moreover, the average degree of polarization and energy efficiency of the apparatus were 82% and 72%, respectively. As compared with the high-performance ultra-collimated nonpolarized backlight module proposed in our prior work, not only did the apparatus exhibit outstanding optical performance, but also the highly polarizedlight emissions actually increased the energy efficiency by 100%.

Full Text Available The polarization characteristics of birefringent tissues could be only partially obtained using linearly polarizedlight in polarization sensitive optical imaging. Here we analyze the change in polarization of backscattered light from birefringent structures versus the orientations of the incident polarizations using linearly, circularly and radially polarizedlight in a cross-polarized confocal microscope. A spatially variable retardation plate composed of eight sectors of λ/2 wave plates was used to transform linearly polarizedlight into a radially polarizedlight. Based on the experimental data obtained from ex-vivo measurements on human scalp hairs and in-vivo measurements on hair and skin, we exemplify that the underestimation of the birefringence content resulting from the orientation related effects associated with the use of linearly polarizedlight for imaging tissues containing wavy birefringent structures could be minimized by using radially polarizedlight.

The polarization characteristics of birefringent tissues could be only partially obtained using linearly polarizedlight in polarization sensitive optical imaging. Here we analyze the change in polarization of backscattered light from birefringent structures versus the orientations of the incident polarizations using linearly, circularly and radially polarizedlight in a cross-polarized confocal microscope. A spatially variable retardation plate composed of eight sectors of λ/2 wave plates was used to transform linearly polarizedlight into a radially polarizedlight. Based on the experimental data obtained from ex-vivo measurements on human scalp hairs and in-vivo measurements on hair and skin, we exemplify that the underestimation of the birefringence content resulting from the orientation related effects associated with the use of linearly polarizedlight for imaging tissues containing wavy birefringent structures could be minimized by using radially polarizedlight.

A spin-polarizing electron beam splitter is described which relies on an arrangement of linearly polarized laser waves of nonrelativistic intensity. An incident electron beam is first coherently scattered off a bichromatic laser field, splitting the beam into two portions, with electron spin and momentum being entangled. Afterwards, the partial beams are coherently superposed in an interferometric setup formed by standing laser waves. As a result, the outgoing electron beam is separated into its spin components along the laser magnetic field, which is shown by both analytical and numerical solutions of Pauli's equation. The proposed laser field configuration thus exerts the same effect on free electrons like an ordinary Stern-Gerlach magnet does on atoms.

Second harmonic generation microscopy was conducted on rat-tail tendons with linearly and radially polarizedbeams. Transverse and axial field components were generated in the focal region through tight focusing of linearly and radially polarized. It was found that the generated SHG signals could not be qualitatively explained with a scalar approximation to the electric field at the focus. Only by accounting for the interactions of the axial and transverse components of the electric field interacting through the nonlinear susceptibility χ(2) tensor could the SHG images be explained. For the case of collagen we find that the SHG signal varies as a function of the analyzer angle with a cos2 or sin2 dependency for linearly polarizedbeams. For tightly focused radially polarizedbeams we find that the output SHG is radially polarized after collimation and is independent of the analyzer angle.

Polarization-induced nanowire light emitting diodes (PINLEDs) are fabricated by grading the Al composition along the c-direction of AlGaN nanowires grown on Si substrates by plasma-assisted molecular beam epitaxy (PAMBE). Polarization-induced charge develops with a sign that depends on the direction of the Al composition gradient with respect to the [0001] direction. By grading from GaN to AlN then back to GaN, a polarization-induced p-n junction is formed. The orientation of the p-type and n-type sections depends on the material polarity of the nanowire (i.e., Ga-face or N-face). Ga-face material results in an n-type base and a p-type top, while N-face results in the opposite. The present work examines the polarity of catalyst-free nanowires using multiple methods: scanning transmission electron microscopy (STEM), selective etching, conductive atomic force microscopy (C-AFM), and electroluminescence (EL) spectroscopy. Selective etching and STEM measurements taken in annular bright field (ABF) mode demonstrate that the preferred orientation for catalyst-free nanowires grown by PAMBE is N-face, with roughly 10% showing Ga-face orientation. C-AFM and EL spectroscopy allow electrical and optical differentiation of the material polarity in PINLEDs since the forward bias direction depends on the p-n junction orientation and therefore on nanowire polarity. Specifically, C-AFM reveals that the direction of forward bias for individual nanowire LEDs changes with the polarity, as expected, due to reversal of the sign of the polarization-induced charge. Electroluminescence measurements of mixed polarity PINLEDs wired in parallel show ambipolar emission due to the mixture of p-n and n-p oriented PINLEDs. These results show that, if catalyst-free III-nitride nanowires are to be used to form polarization-doped heterostructures, then it is imperative to understand their mixed polarity and to design devices using these nanowires accordingly.

We investigate the coupling of the spin angular momentum of lightbeams with elliptical polarization to the spin degree of freedom of free electrons. It is shown that this coupling, which is of similar origin as the well-known spin-orbit coupling, can lead to spin precession. The spin-precession frequency is proportional to the product of the laser-field's intensity and its spin density. The electron-spin dynamics is analyzed by employing exact numerical methods as well as time-dependent perturbation theory based on the fully relativistic Dirac equation and on the nonrelativistic Pauli equation that is amended by a relativistic correction that accounts for the light's spin density.

We demonstrate on-demand control of localized surface plasmons in metamaterials by means of incident lightpolarization. An asymmetric mode, selectively excited by s-polarizedlight, interfere destructively with a bright element, thereby allowing the incident light to propagate at a fairly low loss, corresponding to electromagnetically induced transparency (EIT) in an atomic system. In contrast, a symmetric mode, excited by p-polarizedlight, directly couples with the incident light, which is analogous to the switch-off of EIT. The lightpolarization-dependent excitation of asymmetric and symmetric plasmon modes holds potential for active switching applications of plasmon hybridization.

This report describes the three polarimeters which will be used to measure the beampolarization at the AGS polarizedbeam facility. The beampolarization will be measured before injection into the AGS, during acceleration, and after extraction from the AGS. The 200-MeV polarimeter uses scintillation-counter telescopes to measure the asymmetry in p-carbon inclusive scattering. The internal polarimeter can measure the beampolarization at up to five selected times during acceleration. A continuously spooled nylon filament is swung into the beam at the appropriate time and the asymmetry in pp elastic scattering measured by two scintillation-counter telescopes. This is a relative polarimeter which can be calibrated by the absolute external polarimeter located in the D extracted-beam line. This polarimeter uses scintillation counters in two double-arm magnetic spectrometers to measure clearly the asymmetry in pp elastic scattering from a liquid hydrogen target. The specific features and operation of each polarimeter will be discussed.

This study investigates planar in-vacuo superconducting undulators with periodic length of 5 cm (IVSU5) producing linearly and circularly polarized infrared rays or xrays source. The vertically wound racetrack coil is selected for the coil and pole fabrication of the IVSU5. When the up and down magnetic pole arrays with alternative directions rotated wires in the horizontal plane, a helical field radiates circularly polarizedlight in the electron storage ring, the free electron laser (FEL), and the energy recovery linac (ERL) facilities. Meanwhile, an un-rotated wire is constructed together with the rotated wire on the same undulator is used to switch the linear horizontal and vertical, the right- and left-circular polarization radiation. Given a periodic length of 5 cm and a gap of 23 mm, the maximum magnetic flux density in the helical undulator are Bz = 1.5 T and Bx = 0.5 T when the wires rotated by 20°. This article describes the main factors of the planar and helical undulator design for FEL and...

In this paper, we propose a polarizationbeam splitter utilizing an ultra-thin anisotropic metasurface. The proposed anisotropic element is composed of triple-layered rectangular patches spaced with double-layered dielectric isolators. By tailoring the metallic patches, the cell is capable of transmitting x-polarized waves efficiently and reflecting y-polarizedbeams with almost 100% efficiency at 15 GHz. In addition to this, the reflected phases can be modulated by adjusting the size of the element, which contributes to beam steering in reflection mode. By assigning gradient phases on the metasurface, the constructed sample has the ability to refract x-polarized waves normally and reflect y-polarizedbeams anomalously. For verification, a sample with a size of 240 × 240 mm2 is fabricated and measured. Consistent numerical and experimental results have both validated the efficiently anomalous reflection for y-polarized waves and normal refraction for x-polarizedbeams operating from 14.6-15.4 GHz. Furthermore, the proposed sample has a thickness of 0.1λ at 15 GHz, which provides a promising approach for steering and splitting beams in a compact size.

Optical beam steering is a key element in many industrial and scientific applications like in material processing, information technologies, medical imaging and laser display. Even though galvanometer-based scanners offer flexibility, speed and accuracy at a relatively low cost, they still lack the necessary control over the polarization required for certain applications. We report on the development of a polarization steerable system assembled with a fiber polarization controller and a galvanometric scanner, both controlled by a digital signal processor board. The system implements control of the polarization decoupled from the pointing direction through a feed-forward control scheme. This enables to direct optical beams to a desired direction without affecting its initial polarization state. When considering the full working field of view, we are able to compensate polarization angle errors larger than 0.2 rad, in a temporal window of less than $\\sim 20$ ms. Given the unification of components to fully cont...

Phase only spatial light modulators (SLMs) have become the tool of choice for shaped light generation, allowing the creation of arbitrary amplitude and phase patterns. These patterns are generated using digital holograms and are useful for a wide range of applications as well as for fundamental research. There have been many proposed methods for optimal generation of the digital holograms, all of which perform well under ideal conditions. Here we test a range of these methods under specific experimental constraints, by varying grating period, filter size, hologram resolution, number of phase levels, phase throw and phase nonlinearity. We model beam generation accuracy and efficiency and show that our results are not limited to the specific beam shapes, but should hold for general beam shaping. Our aim is to demonstrate how to optimise and improve the performance of phase-only SLMs for experimentally relevant implementations.

The results on amplifying either radially or azimuthally polarizedlight with a fiber amplifier are presented. Experimental results reveal that more than 85% polarization purity can be retained at the output even with 40dB amplification, and that efficient conversion of the amplified light to linear polarization can be obtained.

We propose a generalized model for the creation of vector Bessel-Gauss (BG) beams having state of polarization (SoP) varying along the propagation direction. By engineering longitudinally varying Pancharatnam-Berry (PB) phases of two constituent components with orthogonal polarizations, we create zeroth- and higher-order vector BG beams having (i) uniform polarizations in the transverse plane that change along z following either the equator or meridian of the Poincaré sphere and (ii) inhomogeneous polarizations in the transverse plane that rotate during propagation along z. Moreover, we evaluate the self-healing capability of these vector BG beams after two disparate obstacles. The self-healing capability of spatial SoP information may enrich the application of BG beams in light-matter interaction, polarization metrology and microscopy.

In the free-space laser communication, there is a strong need for a technology that can decrease the size of the diffraction spot in the receiver port, because a smaller diffraction spot in the receive port makes the transmit data more secure. In this paper, instead of the usage of the larger size aperture lens in the free-space laser communication system, we introduce a diffractive superresolution technology that changing the received information laser beam into radially polarizedbeam which is focused on the detector array. In the paper, firstly, the conversion method of the information natural light which the optical antenna received to the radially polarizedbeam is discussed in detail. Then, in the focal plane, the transverse intensity distribution expression near the focal point for the radially polarized laser beam are presented, and the numerical simulation results of the intensity distributions around the focal point on different numerical apertures (NA) are given. The full width at half-maximum (FWHM) values of the main lobe are considered for the standard of the spot size. Through a comparison of the focal point FWHM values with the natural light and radially polarizedbeam, we judge the superresolution performance of the receiver optical system with radially polarizedbeam on different NA of 0.4, 0.6 and 0.75. We find that the method of focusing with radially polarizedbeam generates a smaller spot size than the Airy spot size when the NA is no less than 0.6; when the NA reach to 0.75, the resolution is 1.5 times than the diffraction limit. But it will decrease the light power in the process of natural light converted to radially polarizedbeam. When the communication laser is polarized laser, the energy loss can be reduced to around 20%. This technology can be applied when the laser energy is not the main concern in the communication.

The spin of a circularly polarizedbeam of light in vacuo is calculated and compared with the value of the spin of a wave packet of light. While the latter has a finite longitudinal and transverse extent, the beam virtually extends indefinitely along the direction of propagation. This fact makes incomplete the textbook calculation of the separation between the spin part and the orbital part of the total angular momentum of a beam of light. Such a calculation contains a three-dimensional integration over the whole space and assumes that the light wave has a finite extent along any direction. This condition is clearly violated by a beam-like wave. Remarkably, this violation yields to an additional observable spin-like part of the angular momentum of the beam. We report an explicit calculation of this novel contribution for both a Gaussian and a Bessel beam, and discuss diverse fundamental facets of this issue.

A metasurface composed of regularly arranged silicon (Si) nanospheres (NSs) with coupling was investigated both theoretically and numerically based on the Mie theory, the simple Lorentz line shape model and the finite-difference time-domain technique. By deliberately controlling the coupling strength between Si NSs through the design of the lattice constants of a rectangular lattice, polarizationbeam splitters, converters and analyzers with good performance can be successfully constructed. A square lattice as well as a large incidence angle was employed to build the polarizationbeam splitters and converters. At an incidence angle of 80°, the polarizationbeam splitters can completely reflect the s-polarizedlight and transmit the p-polarizedlight in a wavelength region of 510-620 nm. For a circularly polarizedlight incident on the polarization converters, one can get s-polarizedlight in the reflection direction and p-polarizedlight in the transmission direction. For the polarizationbeam analyzers, a rectangular lattice with deliberately chosen lattice constants was employed and the transmissivity of a linearly polarizedlight can be continuously adjusted from 0 to ~0.90 by simply rotating the metasurface. We revealed that the broadening of either the electric dipole resonance or the magnetic dipole resonance or both of them, which is induced by the asymmetric coupling of Si NSs, is responsible for the modification in the transmissivity spectrum of the metasurface. Our findings provide a guideline for designing photonic devices based on the metasurfaces composed of Si NSs with controllable coupling strength.

We studied depolarization mechanisms of polarized proton acceleration in high energy accelerators with snakes and found that the perturbed spin tune due to the imperfection resonance plays an important role in beam depolarization at snake resonances. We also found that even order snake resonances exist in the overlapping intrinsic and imperfection resonances. Due to the perturbed spin tune of imperfection resonances, each snake resonance splits into two. Thus the available betatron tune space becomes smaller. Some constraints on polarizedbeam colliders were also examined.

Natural sources of light are at best weakly polarized, but polarization of light is common in natural scenes in the atmosphere, on the surface of the Earth, and underwater. We review the current state of knowledge concerning how polarization and polarization patterns are formed in nature, emphasizing linearly polarizedlight. Scattering of sunlight or moonlight in the sky often forms a strongly polarized, stable and predictable pattern used by many animals for orientation and navigation throughout the day, at twilight, and on moonlit nights. By contrast, polarization of light in water, while visible in most directions of view, is generally much weaker. In air, the surfaces of natural objects often reflect partially polarizedlight, but such reflections are rarer underwater, and multiple-path scattering degrades such polarization within metres. Because polarization in both air and water is produced by scattering, visibility through such media can be enhanced using straightforward polarization-based methods of image recovery, and some living visual systems may use similar methods to improve vision in haze or underwater. Although circularly polarizedlight is rare in nature, it is produced by the surfaces of some animals, where it may be used in specialized systems of communication.

Field measurements have demonstrated that sunlight polarized during a first surface reflection by shiny leaves dominates the optical polarization of the light reflected by shiny-leafed plant canopies having approximately spherical leaf angle probability density functions ("Leaf Angle Distributions" - LAD). Yet for other canopies - specifically those without shiny leaves and/or spherical LADs - potential sources of optically polarizedlight may not always be obvious. Here we identify possible sources of polarizedlight within those other canopies and speculate on the ecologically important information polarization measurements of those sources might contain.

In a historical review, the observations and the insight gained from polarization studies of fast ions interacting with solid targets are presented. These began with J. Macek's recognition of zero-field quantum beats in beam-foil spectroscopy as indicating alignment, and D.G. Ellis' density operator analysis that suggested the observability of orientation when using tilted foils. Lastly H. Winter's studies of the ion-beam surface interaction at grazing incidence yielded the means to produce a high degree of nuclear orientation in ion beams.

We consider polarization changes of randomly fluctuating electromagnetic pulsed light in temporal imaging. The polarization properties of pulses formed by the time lens are formulated in terms of the Stokes parameters. For Gaussian Schell-model pulses we show that the degree and state of polarization of the time-imaged pulse can be tailored in versatile ways, depending on the temporal polarization and coherence of the input pulse and the system parameters. In particular, weakly polarized central region of the pulse may become fully polarized without energy absorption. The results have potential applications in optical communication, micromachining, and light-matter interactions.

Spin orbit interaction and the resulting Spin Hall effect of light are under recent intensive investigations because of their fundamental nature and potential applications. Here, we report an extraordinary spin specific beam shift of light and demonstrate its tunability in an inhomogeneous anisotropic medium exhibiting spatially varying retardance level. The spin specificity (shift occurs only for one circular polarization mode, keeping the other orthogonal mode unaffected) is shown to arise due to the combined spatial gradients of the geometric phase and the dynamical phase of light. The constituent two orthogonal circular polarization modes of an input linearly polarizedlight evolve in different trajectories, eventually manifesting as a large and tunable spin separation. The spin specificity of the beam shift and the demonstrated principle of simultaneously tailoring space-varying geometric and dynamical phase of light for achieving its tunability (of both magnitude and direction), may provide an attractiv...

This paper describes a time-marking system that enables a measurement of the in-plane (horizontal) polarization of a 0.97-GeV/c deuteron beam circulating in the Cooler Synchrotron (COSY) at the Forschungszentrum Jülich. The clock time of each polarimeter event is used to unfold the 120-kHz spin precession and assign events to bins according to the direction of the horizontal polarization. After accumulation for one or more seconds, the down-up scattering asymmetry can be calculated for each direction and matched to a sinusoidal function whose magnitude is proportional to the horizontal polarization. This requires prior knowledge of the spin tune or polarization precession rate. An initial estimate is refined by resorting the events as the spin tune is adjusted across a narrow range and searching for the maximum polarization magnitude. The result is biased toward polarization values that are too large, in part because of statistical fluctuations but also because sinusoidal fits to even random data will produce sizable magnitudes when the phase is left free to vary. An analysis procedure is described that matches the time dependence of the horizontal polarization to templates based on emittance-driven polarization loss while correcting for the positive bias. This information will be used to study ways to extend the horizontal polarization lifetime by correcting spin tune spread using ring sextupole fields and thereby to support the feasibility of searching for an intrinsic electric dipole moment using polarizedbeams in a storage ring. This paper is a combined effort of the Storage Ring EDM collaboration and the JEDI collaboration.

A fast response polarizedlight microscope was designed based on the algorithm by Shribak et. al (Applied Optics, vol. 42, 3009-3017). A pulsed laser beam was passed through two Pockels cells aligned at different angles with respect to optical axis. The retardance of the Pockels cell was controlled by external switches and power supplies. The electronics circuit in the system allows change of the retardance of the Pockels cell each millisecond for four milliseconds. In four milliseconds, four images of a birefringent sample, formed by different states of polarizedlight are recorded. The images are added appropriately to calculate retardence amplitude and phase by using codes written in imageJ software. The microscope was used to show the retardance and phase of a rabbit muscle fiber. Recordings were also taken of the contraction of Vorticella convallaria but the changes were too fast to yield retardance images. This type of microscope can be used to study different kinds of biological functions that change on a timescale slower than four milliseconds but faster than two seconds.

The scattering of a Linearly Polarized Bessel Beam (LPBB) by an isotropic and homogenous dielectric sphere is investigated. Using analytical relation between the cylindrical and the spherical vector wave functions, all the closed- form analytical expressions, in terms of spherical wave-functions expansions, are derived for the scattered field. It is shown that in the case of conical angle of incident Bessel beam is equal to zero, the Linearly Polarized Bessel Beam becomes a plane wave and its scattering coefficients become the same as the expansion coefficients of plane wave in Mie theory. The transverse Cartesian and spherical components of the electric field, scattered by a sphere are shown in the z-plane for different cases, moreover the intensity of the incident Bessel beam and the effects of its conical angle on the scattered field and the field inside the sphere are investigated. To quantitatively study the scattering phenomenon and the variations of the fields inside and outside of the sphere, the scattering and absorption efficiencies are obtained for the scattering of the linearly-polarized Bessel beam, and are compared with those of the plane wave scattering.

Helicity-dependent photocurrent delta-I has been detected successfully under experimental configuration that a circularly polarizedlightbeam is impinged with a right angle on a cleaved sidewall of the Fe/x-AlOx/GaAs-based n-i-p double-heterostructure. The photocurrent delta-I has showed a well-defined hysteresis loop which resembles that of the magnetization of the in-plane magnetized Fe layer in the devices. The value of delta-I has been |delta-I|~0.2 nA at 5 K under the remnant magnetization state. Study on temperature dependence of the relative delta-I value at H = 0 has revealed that it is maximized at temperatures 125 - 150 K, and is still measurable at room temperature.

I perform tracking simulations to fit various measurements of the polarization for a stored uncooled polarized deuteron beam, published in the recent paper by Benati et. al (P. Benati {\\em et al.}, {\\it Phys. Rev. ST Accel. Beams} {\\bf 15}, 124202 (2012)). The collaboration kindly sent me datafiles of the polarization measurements, and also pertinent details of the experimental data acquisition procedure. The latter are essential to obtain quantitative fits to the data. I describe my findings and inferences from the data. In some cases I offer alternative interpretations of the data from that given by Benati et. al. I also correct some mistakes in my recent paper (S. R. Mane, {\\em Nucl. Inst. Meth.} {\\bf 726} 104--112 (2013)).

The spin of the proton has been investigated with polarizedbeams and targets for decades and has led to our current picture of the kinematic and partonic structure of the proton's spin. Historically, this picture has relied heavily on data from Deep Inelastic Scattering of polarized leptons and is still mainly influenced by this framework. Over the past decade, operation of the RHIC/AGS has vastly increased the amount of data from collisions of polarized proton beams. Much theoretical and experimental work has been done to understand such probes as pions, jets, and Z/Ws especially with the STAR, PHENIX, BRAHMS, AnDY and pp2pp detectors. I will present an overview of the capabilities of the RHIC complex and demonstrate how measurements from many experiments are complementing and expanding our understanding of the proton spin.

We report on the morphological effects induced by the inhomogeneous absorption of radially polarized femtosecond laser irradiation of nickel (Ni) in sub-ablation conditions. A theoretical prediction of the morphology profile is performed, and the role of surface plasmon excitation in the production of self-formed periodic ripple structures is evaluated. Results indicate a smaller periodicity of the ripples profile compared to that attained under linearly polarized irradiation conditions. A combined hydrodynamical and thermoelastic model is presented in laser beam conditions that lead to material melting. The simulation results are presented to be in good agreement with the experimental findings. The ability to control the size of the morphological changes via modulating the beampolarization may provide an additional route for controlling and optimizing the outcome of laser micro-processing.

The total intensity of light transmitted at non-normal incidence thorough planar metamaterials can be different for forward and backward propagation. For metamaterial patterns of different symmetries we observe this effect for circularly or linearly polarizedlight.

We have studied the rotation of an elliptically polarizedlight propagating through thermal rubidium vapor with efficient four-wave mixing (FWM) and cross-phase modulation (XPM). These nonlinear processes are enhanced by Zeeman coherence within the degenerate sub-levels of the two-level atomic system. The elliptically polarizedlight with small ellipticity is considered as the superposition of a strong-linearly-polarized pump beam and a weak-orthogonal-polarized probe beam. The interference of the probe and the newly generated light field due to degenerate FWM and their gain in the medium due to a large XPM induced by the pump beam leads to the rotation of the elliptical polarizedlight. A theoretical analysis of the probe propagation through the nonlinear medium was used to explain the experimental observation and the fitting of the experimental data gives the estimates of the third-order non-linear susceptibilities associated with FWM and XPM. Our study can provide useful parameters for the generation of efficient squeezed vacuum states and squeezed polarization states of light. Furthermore our study finds application in controlling the diffraction of a linearly-polarizedlightbeam traversing the medium.

Full Text Available We experimentally measured the self-healing of the spatially inhomogeneous states of polarization of vector Bessel beams. Radially and azimuthally polarized vector Bessel beams were experimentally generated via a digital version of Durnin's method...

Polarizingbeam splitter (PBS) is a critical optical component in projection display system because PBS performance greatly influences the contrast and brightness of the system. PBS performance is usually measured by spectrophotometer after coating and cementing, but the measured result cannot represent the actual performance in practice because people usually change the incident angle in one plane (horizontal plane) and do not consider the other plane (vertical plane). Geometrical polarization rotation occurring at reduced F-number influences the measuring precision of s-polarization transmittance (Ts) and p-polarization reflectance (Rp). A more accurate and practical way to measure the performance of broadband, wide-angle PBS is presented in this paper.

We have observed depolarization effects when high intensity cold neutron beams are incident on alkali-metal-spin-exchange polarized He-3 cells used as neutron spin filters. This was first observed as a reduction of the maximum attainable He-3 polarization and was attributed to a decrease of alkali-metal polarization, which led us to directly measure alkali-metal polarization and spin relaxation over a range of neutron fluxes at LANSCE and ILL. The data reveal a new alkali-metal spin-relaxation mechanism that approximately scales as the square root of the neutron capture-flux density incident on the cell. This is consistent with an effect proportional to the recombination-limited ion concentration, but is much larger than expected from earlier work.

A simple way to create dynamic photonic crystals with different lattice symmetry by interference of non-coplanar laser beams in colloidal solution of quantum dots was demonstrated. With the proposed technique we have made micro-periodic dynamic semiconductor structure with strong nonlinear changing of refraction and absorption and analyzed the self-diffraction processes of two, three and four non-coplanar laser beams at the dynamic photonic crystal (diffraction grating) with hexagonal lattice structure. To reach the best uniform contrast of the structure and for better understanding of the problems, specially raised by the interference of multiple laser beams theoretical calculation of the periodic intensity field in the QDs solution were performed. It was demonstrated that dynamic photonic crystal structure and even it's dimension can be easily tuned with a high speed by the laser beamspolarization variation without changing the experimental setup geometry.

The assessment of the activation of the otolith gravitoinertial sensors in the vestibular system of the inner ear may be accomplished by observing the occular counterrolling (OCR) movements which rotate the eyes about the line of sight. A method is presented for the continuous measurement of OCR by means of polarizedlight, a system of polarizers, and a contact lens. A polarized hard contact lens is placed between two soft lenses before application to the eye, and the measured phase difference between the incident rotating polarizedlight and the reflected light from this lens provides readings uncontaminated by other eye movement modes.

We use the quantum kinematic approach to revisit geometric phases associated with polarizing processes of a monochromatic light wave. We give the expressions of geometric phases for any, unitary or non-unitary, cyclic or non-cyclic transformations of the light wave state. Contrarily to the usually considered case of absorbing polarizers, we found that a light wave passing through a polarizer may acquire in general a non zero geometric phase. This geometric phase exists despite the fact that initial and final polarization states are in phase according to the Pancharatnam criterion and can not be measured using interferometric superposition. Consequently, there is a difference between the Pancharatnam phase and the complete geometric phase acquired by a light wave passing through a polarizer. We illustrate our work with the particular example of total reflection based polarizers.

The temporal evolution of photoinduced birefringence is investigated on the basis of a model proposed by Pedersen and co-workers, This model is extended for the case of elliptically polarizedlight, and used to describe the erasure of photoinduced birefringence by circularly polarizedlight...

By use of a tensor method, the transform formulae for the beam coherence-polarization matrix of the partially polarized Gaussian Schell-model (GSM) beams through aligned and misaligned optical systems are derived. As an example, the propagation properties of the partially polarized GSM beam passing through a misaligned thin lens are illustrated numerically and discussed in detail. The derived formulae provide a convenient way to study the propagation properties of the partially polarized GSM beams through aligned and misaligned optical systems.

The meiotic spindle structure plays a key role in normal chromosome alignment and segregation during meiosis. Polarizedlight microscopy (PLM) allows non-invasive evaluation of the meiotic spindle of metaphase oocytes from different animal species. The purpose of this article is to review the use of PLM in animal reproduction, mainly in the assessment of the meiotic spindle in oocytes. A brief overview of the methods to assess the meiotic spindle is presented as well as the principles behind the PLM. The use of PLM to evaluate oocyte quality and spindle morphology is discussed and the results on the viability of the oocytes after being exposed to PLM are presented. Several researchers showed that PLM could be successfully implemented on cryopreservation, nuclear transfer and intracytoplasmic sperm injection procedures as a tool to improve the outcome of these procedures. In addition, PLM can be used to develop studies on oocyte maturation and spindle dynamics. However, the information on the practical use of this technology in farm animals is very limited and further studies are needed to assess the importance of PLM in animal reproduction.

When polarized electrons traverse a region where the laser light is focused their polarization varies even if their energy and direction of motion are not changed. This effect is due to interference of the incoming electron wave and an electron wave scattered at zero angle. Equations are obtained which determine the variation of the electron density matrix, and their solutions are given. The change in the electron polarization depends not only on the Compton cross section but on the real part of the forward Compton amplitude as well. It should be taken into account, for example, in simulations of the $e \\to \\gamma$ conversion for future $\\gamma \\gamma$ colliders.

We present a study of geometric phases in classical wave and polarisation optics using the basic mathematical framework of quantum mechanics. Important physical situations taken from scalar wave optics, pure polarisation optics, and the behaviour of polarisation in the eikonal or ray limit of Maxwell's equations in a transparent medium are considered. The case of a beam of light whose propagation direction and polarisation state are both subject to change is dealt with, attention being paid to the validity of Maxwell's equations at all stages. Global topological aspects of the space of all propagation directions are discussed using elementary group theoretical ideas, and the effects on geometric phases are elucidated.

Both attraction and repulsion from linearly polarizedlight have been observed in zooplankton. A dichotomous choice experiment, consisting of plankton light traps deployed in natural waters at a depth of 30 m that projected either polarized or unpolarized light of the same intensity, was used to test the hypothesis that the North Atlantic copepod, Calanus spp., is linearly polarotactic. In addition, the transparency of these copepods, as they might be seen by polarization insensitive vs. sensitive visual systems, was measured. Calanus spp. exhibited negative polarotaxis with a preference ratio of 1.9:1. Their transparency decreased from 80% to 20% to 30% in the unpolarized, partially polarized, and electric (e-) vector orientation domains respectively - that is, these copepods would appear opaque and conspicuous to a polarization-sensitive viewer looking at them under conditions rich in polarizedlight. Since the only difference between the two plankton traps was the polarization cue, we conclude that Calanus spp. are polarization sensitive and exhibit negative polarotaxis at low light intensities (albeit well within the sensitivity range reported for copepods). We hypothesize that Calanus spp. can use polarization vision to reduce their risk of predation by polarization-sensitive predators and suggest that this be tested in future experiments.

Both attraction and repulsion from linearly polarizedlight have been observed in zooplankton. A dichotomous choice experiment, consisting of plankton light traps deployed in natural waters at a depth of 30 m that projected either polarized or unpolarized light of the same intensity, was used to test the hypothesis that the North Atlantic copepod, Calanus spp., is linearly polarotactic. In addition, the transparency of these copepods, as they might be seen by polarization insensitive vs. sensitive visual systems, was measured. Calanus spp. exhibited negative polarotaxis with a preference ratio of 1.9:1. Their transparency decreased from 80% to 20% to 30% in the unpolarized, partially polarized, and electric (e-) vector orientation domains respectively - that is, these copepods would appear opaque and conspicuous to a polarization-sensitive viewer looking at them under conditions rich in polarizedlight. Since the only difference between the two plankton traps was the polarization cue, we conclude that Calanus spp. are polarization sensitive and exhibit negative polarotaxis at low light intensities (albeit well within the sensitivity range reported for copepods). We hypothesize that Calanus spp. can use polarization vision to reduce their risk of predation by polarization-sensitive predators and suggest that this be tested in future experiments.

We demonstrate that an array of optical antennas may render a thin layer of randomly oriented semiconductor nanocrystals into an enhanced and highly directional source of polarizedlight. The array sustains collective plasmonic lattice resonances which are in spectral overlap with the emission of the nanocrystals over narrow angular regions. Consequently, di?fferent photon energies of visible light are enhanced and beamed into def?nite directions.

Polarization-singularity C-points, a form of line singularities, are the vectorial counterparts of the optical vortices of spatial modes and fundamental optical features of polarization-spatial modes. Their generation in tailored beams has been limited to lemon and star C-points that contain symmetric dislocations in state-of-polarization patterns. In this article we present the theory and laboratory measurements of two complementary methods to generate isolated asymmetric C-points in tailored beams, of which symmetric lemons and stars are limiting cases; and we report on the generation of monstars, an asymmetric C-point with characteristics of both lemons and stars.

We present a geometric-analytic introductory treatment of polarization based on the circular polarization basis, which connects directly to the Poincaré sphere. This treatment enables a more intuitive way to arrive at the polarization ellipse from the components of the field. We also present an advanced optics lab that uses Poincaré beams, which have a polarization that is spatially variable. The physics of this lab can reinforce understanding of all states of polarization, and in particular, elliptical polarization. In addition, it exposes students to Laguerre-Gauss modes, the spatial modes used in creating Poincaré beams, which have unique physical properties. In performing this lab, students gain experience in experimental optics, such as aligning and calibrating optical components, using and programming a spatial light modulator, building an interferometer, and performing polarimetry measurements. We present the apparatus for doing the experiments, detailed alignment instructions, and lower-cost alternatives.

A breadboard version of an optical beam combiner is depicted which make it possible to use the outputs of any or all of four multimode laser diodes to pump a non-planar ring oscillator (NPRO) laser. The output of each laser diode has a single-mode profile in the meridional plane containing an axis denoted the 'fast' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis. One of the purposes served by the beam-combining optics is to reduce the fast-axis numerical aperture (NA) of the laser-diode output to match the NA of the optical fiber. Along the slow axis, the unmodified laser-diode NA is already well matched to the fiber optic NA, so no further slow-axis beam shaping is needed. In this beam combiner, the laser-diode outputs are collimated by aspherical lenses, then half-wave plates and polarizingbeam splitters are used to combine the four collimated beams into two beams. Spatial combination of the two beams and coupling into the optical fiber is effected by use of anamorphic prisms, mirrors, and a focusing lens. The anamorphic prisms are critical elements in the NA-matching scheme, in that they reduce the fast-axis beam width to 1/6 of its original values. Inasmuch as no slow-axis beam shaping is needed, the collimating and focusing lenses are matched for 1:1 iumaging. Because these lenses are well corrected for infinite conjugates the combiner offers diffraction-limited performance along both the fast and slow axes.

We suggest a novel mechanism to induce the motion of a chiral material body towards an optical source. Our solution is based on the interference between a chiral lightbeam and its reflection on an opaque mirror. Surprisingly, it is theoretically shown that the electromagnetic response of the material may be tailored in such a way that independent of the specific body location with the respect to the mirror, it is always pushed upstream against the photon flow associated with the incoming wave. Moreover, it is proven that by controlling the handedness of the incoming light it may be possible to harness the sign of the optical force, switching from a pulling force to a pushing force.

We demonstrate the possibility to switch the z-polarization component of the illumination in the vicinity of the focus of high-NA objective lenses by applying radially and azimuthally polarized incident light. The influence of the field distribution on nonlinear effects was first investigated by the means of simulations. These were performed for high-NA objective lenses commonly used in nonlinear microscopy. Special attention is paid to the influence of the polarization of the incoming field. For linearly, circularly and radially polarizedlight a considerable polarization component in z-direction is generated by high NA focusing. Azimuthal polarization is an exceptional case: even for strong focusing no z-component arises. Furthermore, the influence of the input polarization on the intensity contributing to the nonlinear signal generation was computed. No distinct difference between comparable input polarization states was found for chosen thresholds of nonlinear signal generation. Differences in signal generation for radially and azimuthally polarized vortex beams were experimentally evaluated in native collagen tissue (porcine cornea). The findings are in good agreement with the theoretical predictions and display the possibility to probe the molecular orientation along the optical axis of samples with known nonlinear properties. The combination of simulations regarding the nonlinear response of materials and experiments with different sample orientations and present or non present z-polarization could help to increase the understanding of nonlinear signal formation in yet unstudied materials. PMID:25071961

As a rule, an intensity spectrum of undulator radiation (UR) is calculated by using the classical approach, even for electron energy higher than 10 GeV. Such a spectrum is determined by an electron trajectory in an undulator while neglecting radiation loss. Using Planck's law, the UR photon spectrum can be calculated from the obtained intensity spectrum, for both linear and nonlinear regimes. The electron radiation process in a field of strong electromagnetic waves is considered within the quantum electrodynamics framework, using the Compton scattering process or radiation in a 'light' undulator. A comparison was made of the results from using these two approaches, for UR spectra generated by 250-GeV electrons in an undulator with a 11.5-mm period; this comparison shows that they coincide with high accuracy. The characteristics of the collimated UR beam (i.e. spectrum and circular polarization) were simulated while taking into account the discrete process of photon emission along an electron trajectory in both undulator types. Both spectral photon distributions and polarization dependence on photon energy are 'smoothed', in comparison to that expected for a long undulator-the latter of which considers the ILC positron source (ILC Technical Design Report).

By arranging the particle first banana orbits to pass near a distant detector, the light ion beam probe (LIBP) utilizes orbital deflection to probe internal fields and field fluctuations. The LIBP technique takes advantage of (1) the in situ, known source of fast ions created by beam-injected neutral particles that naturally ionize near the plasma edge and (2) various commonly available diagnostics as its detector. These born trapped particles can traverse the plasma core on their inner banana leg before returning to the plasma edge. Orbital displacements (the forces on fast ions) caused by internal instabilities or edge perturbing fields appear as modulated signal at an edge detector. Adjustments in the q-profile and plasma shape that determine the first orbit, as well as the relative position of the source and detector, enable studies under a wide variety of plasma conditions. This diagnostic technique can be used to probe the impact on fast ions of various instabilities, e.g., Alfvén eigenmodes (AEs) and neoclassical tearing modes, and of externally imposed 3D fields, e.g., magnetic perturbations. To date, displacements by AEs and by externally applied resonant magnetic perturbation fields have been measured using a fast ion loss detector. Comparisons with simulations are shown. In addition, nonlinear interactions between fast ions and independent AE waves are revealed by this technique.

In this thesis we investigate devices needed to handle the polarization of thermal neutron beams: π/2- flippers (to start/stop Larmor precession) and π- flippers (to reverse polarization/ precession direction) and illustrate how these devices are used to investigate the properties of matter and of the neutron. The central theme is: demonstration—for the full thermal spectrum—of a special mode of Larmor precession (called “zero-field”-precession) over the neutron beam path length between two “adiabatic Radio-Frequency flippers”. This technique enables one to build neutron spin-echo spectrometers with exceedingly large precession angles, without applying magnetic fields over long distances (meters). As an extension of this demonstration, a prototype S&barbelow;pin-E&barbelow;cho instrument for S&barbelow;mall A&barbelow;ngle N&barbelow;eutron S&barbelow;cattering (SESANS) was built, based on similar flippers with s...

Optically pumped alkali metal atoms currently provide a sensitive solution for magnetic microscopic measurements. As the most practicable plan, Faraday rotation of linearly polarizedlight is extensively used in spin polarization measurements of alkali metal atoms. In some cases, near-resonant Faraday rotation is applied to improve the sensitivity. However, the near-resonant linearly polarized probe light is elliptically polarized after passing through optically pumped alkali metal vapor. The ellipticity of transmitted near-resonant probe light is numerically calculated and experimentally measured. In addition, we also analyze the negative impact of elliptical polarization on Faraday rotation measurements. From our theoretical estimate and experimental results, the elliptical polarization forms an inevitable error in spin polarization measurements.

1012) range. The polarization is thus a convolution of the electric field at previous times with the time- dependent susceptibility. In the case of a...by the following: (a) Commence with () and cos(), separately , and delay each constituent beam by /2, separately , to...3.1, above). A example of continuation of the analysis procedure. Probability density measures were calculated based on a normal kernel function for

Efficiency of liquid crystal displays highly depends on the amount of polarizedlight emerging from the backlight module. In this paper, a backlight architecture using a nanoimprint wire grid polarizer for polarization recycling is proposed and studied, in which the extraction efficiency of polarizedlight is the major concern. The backlight module is composed of the stack of a wire grid polarizer, a lenticular array and a light guide plate. The light guide plate features interleaving v-groove and trapezoidal ridge coated with aluminum on the top surface, and scattering dot array on the bottom. The angular divergence of emerging light from the light guide plate can be well constrained so as to exploit the angular range with the best transmission of polarizedlight for the wire grid polarizer. The prototype of a 2.5-inch module has demonstrated an angular divergence of 48°. The overall extraction efficiency of polarizedlight enhanced by 21% and uniformity of 76% have been achieved.

Full Text Available ky polarization patterns can be used both as indicators of atmospheric turbidity and as a sun compass for navigation. The objective of this study is to improve the precision of sky lightpolarization measurements by optimal design of the device used. The central part of the system is composed of a Charge Coupled Device (CCD camera; a fish-eye lens and a linear polarizer. Algorithms for estimating parameters of the polarizedlight based on three images are derived and the optimal alignments of the polarizer are analyzed. The least-squares estimation is introduced for sky lightpolarization pattern measurement. The polarization patterns of sky light are obtained using the designed system and they follow almost the same patterns of the single-scattering Rayleigh model. Deviations of polarization angles between observation and the theory are analyzed. The largest deviations occur near the sun and anti-sun directions. Ninety percent of the deviations are less than 5° and 40% percent of them are less than 1°. The deviations decrease evidently as the degree of polarization increases. It also shows that the polarization pattern of the cloudy sky is almost identical as in the blue sky.

The light reflected from scarab beetles illuminated with unpolarized white light is analyzed ellipsometrically and displayed as the sum of an elliptically polarized spectrum Ip and an unpolarized spectrum Iu. A chirped stack of chiral resonators, each with a characteristic Bragg wavelength and partial realignment of birefringent material to a fixed axis, is proposed as a model for simulation of both reflection and polarization spectra. Possible mechanisms that effectively eliminate impedance mismatch at the air-elytron interface and allow some beetles to exhibit nearly perfect circularly polarized reflections are discussed. Results are presented for three representative beetles, Ischiosopha bifasciata, which is shown to be a narrowband left-circular polarizer; Chrysophora chrysochlora, a broadband left-circular polarizer; and Chrysina woodi, an elliptical polarizer. The methods that are developed are applicable to the more general problem of synthesis of reflectors with prescribed reflection and polarization spectra.

This paper describes a time-marking system that enables a measurement of the in-plane (horizontal) polarization of a 0.97-GeV/c deuteron beam circulating in the Cooler Synchrotron (COSY) at the Forschungszentrum J\\"ulich. The clock time of each polarimeter event is used to unfold the 120-kHz spin precession and assign events to bins according to the direction of the horizontal polarization. After accumulation for one or more seconds, the down-up scattering asymmetry can be calculated for each direction and matched to a sinusoidal function whose magnitude is proportional to the horizontal polarization. This requires prior knowledge of the spin tune or polarization precession rate. An initial estimate is refined by re-sorting the events as the spin tune is adjusted across a narrow range and searching for the maximum polarization magnitude. The result is biased toward polarization values that are too large, in part because of statistical fluctuations but also because sinusoidal fits to even random data will prod...

The Mueller matrix represents the transfer function of an optical system in its interactions with polarizedlight and its elements relate to specific biologically or clinically relevant properties. However, when many optical polarization effects occur simultaneously, the resulting matrix elements represent several "lumped" effects, thus hindering their unique interpretation. Currently, no methods exist to extract these individual properties in turbid media. Here, we present a novel application of a Mueller matrix decomposition methodology that achieves this objective. The methodology is validated theoretically via a novel polarized-light propagation model, and experimentally in tissue simulating phantoms. The potential of the approach is explored for two specific biomedical applications: monitoring of changes in myocardial tissues following regenerative stem cell therapy, through birefringence-induced retardation of the light's linear and circular polarizations, and non-invasive blood glucose measurements through chirality-induced rotation of the light's linear polarization. Results demonstrate potential for both applications.

Nanoscale light source is the key element for on-chip integrated optical communication system. As an important property of light source, polarization can be exploited to improve the information capacity of optical communication and the sensitivity of optical sensing. We demonstrate a novel TE-polarizedlight source based on graphene-nanoribbon (G-NR) hybrid structure. Thanks to the polarizing dependent absorption along graphene layer, the random polarized emission of nanoribbon (NR) can be transferred into the same TE polarization. In addition, lasing action in G-NR hybrid structure is also investigated. We attribute the polarization control to the differential attenuation of electromagnetic modes in graphene. Our simulation revealed electromagnetic field distribution and far field polar images of TE and TM modes in nanoribbon, which is consistent with experimental results. The compact G-NR hybrid structure light source offers a new way to realize the polarization controllable nanoscale light source and facilitate the practical applications of nanowire or nanoribbon light source.

This article gives an analysis of the behavior of polarizing grids and reflecting polarizers by solving Maxwell's equations, for arbitrary angles of incidence and grid rotation, for cases where the excitation is provided by an incident plane wave or a beam of radiation. The scattering and impedance matrix representations are derived and used to solve more complicated configurations of grid assemblies. The results are also compared with data obtained in the calibration of reflecting polarizers at the Owens Valley Radio Observatory (OVRO). From this analysis, we propose a method for choosing the optimum grid parameters (wire radius and spacing). We also provide a study of the effects of two types of errors (in wire separation and radius size) that can be introduced in the fabrication of a grid.

In the optical pumping systems based on the pump-probe arrangement, the spin polarization of the atoms is generally monitored utilizing the probe laser beam, in which way an extra perturbation must be introduced and thus affects the normal operation of the sensors. By investigating the absorption rate of the circularly polarized pump laser, here we demonstrate the feasibility of extracting the electron-spin polarization from the transmitted pump laser intensity. We experimentally validate the method in a spin-exchange relaxation free (SERF) magnetometer and the results are in excellent agreement with the theory. The scheme operates in a silent mode and features a real-time observation. We also study the corresponding magnetic field response of the SERF magnetometer and a term arising from the diffusion effects has been added to the original model to explain the discrepancy of the response.

The property of the FEL polarization is of great importance to the user community. FEL pulses with ultra-high intensity and flexible polarization control ability will absolutely open up new scientific realms. In this paper, several polarization control approaches are presented to investigate the great potential on Dalian coherent light source, which is a government-approved novel FEL user facility with the capability of wavelength continuously tunable in the EUV regime of 50-150 nm. The numerical simulations show that both circularly polarized FELs with highly modulating frequency and 100 microjoule level pulse energy could be generated at Dalian coherent light source.

We investigated the variations in generated white-light when crossing two femtosecond laser beams in a Kerr medium. By changing the relative delay of two interacting intense femtosecond laser pulses, we show that white-light generation can be enhanced or suppressed. With a decrease of the relative delay an enhancement of the white-light output was observed, which at even smaller delays was reverted to a suppression of white-light generation. Under choosen conditions, the level of suppression resulted in a white-light output lower than the initial level corresponding to large delays, when the pulses do not overlap in time. The enhancement of the white-light generation takes place in the pulse that is lagging. We found that the effect of the interaction of the beams depends on their relative orientation of polarization and increases when the polarizations are changed from perpendicular to parallel. The observed effects are explained by noting that at intermediate delays, the perturbations introduced in the path of the lagging beam lead to a shortening of the length of filament formation and enhancement of the white-light generation, whereas at small delays the stronger interaction and mutual rescattering reduces the intensity in the central part of the beams, suppressing filamentation and white-light generation.

Photoacoustic transformation of the TE mode of a Bessel lightbeam (BLB) has been studied for piezoelectric detection in short-period superlattices formed by magnetoactive crystals of bismuth germanate (Bi{sub 12}GeO{sub 20}) and bismuth silicate (Bi{sub 12}SiO{sub 20}) types. It is shown that the resulting signal amplitude can be controlled using optical schemes of BLB formation with a tunable cone angle. A resonant increase in the signal amplitude has been found in the megahertz range of modulation frequencies and its dependences on the BLB modulation frequency, geometric sizes of the two-layer structure and piezoelectric transducer, radial coordinate of the polarization BLB mode, and dissipative superlattice parameters are analyzed.

Studies of polarized radiation from molecular clouds and the environments of protostars are providing information about the orientations and strengths of magnetic fields and the sizes andcompositions of dust grains in these environments.

Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarizedlight, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarizedlight cues in a four-arm "plus" maze. The birds did not use overhead polarizedlight near the zenith for sky compass orientation. Instead, overhead polarizedlight modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarizedlight axis aligned parallel to the magnetic field. When the polarizedlight axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarizedlight and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth's magnetic field.

Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarizedlight, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarizedlight cues in a four-arm “plus” maze. The birds did not use overhead polarizedlight near the zenith for sky compass orientation. Instead, overhead polarizedlight modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarizedlight axis aligned parallel to the magnetic field. When the polarizedlight axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarizedlight and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth’s magnetic field. PMID:26811473

The nucleon polarizabilities are fundamental structure observables, like the nucleon mass or charge. While the electric (αE 1) and magnetic (βM 1) scalar polarizabilities of the nucleon have been measured, little effort has been made to extract the spin dependent polarizabilities. These nucleon polarizabilities, γE1E1 ,γM1M1 ,γM1E2 and γE1M2 describe the spin response of a proton to electric and magnetic dipole and quadrupole interactions. We plan to extract them using polarized photon beam and polarized target at the MAMI tagged photon facility in Mainz, Germany. This requires precise measurement of the double polarization observable ∑2 z which is sensitive to these polarizabilities. The ∑2 z is measured via a circularly polarized photon beam on a longitudinally polarized butanol target in the resonance region (E = 250 - 310 MeV). Together with constraints from αE 1 and βM 1, the forward spin polarizability (γ0) , and QCD based models, should allow us to extract all four spin polarizabilities. This presentation will be focused on the preliminary experimental results for the measurement of ∑2 z at different energies and angles. Supported by the Natural Sciences and Engineering Research Council of Canada (NSERC).

Classical ghost imaging is a correlation-imaging technique in which the image of the object is found through intensity correlations of light. We analyze three different quality parameters, namely the visibility, the signal-to-noise ratio (SNR), and the contrast-to-noise ratio (CNR), to assess the performance of double- and triple-intensity correlation-imaging setups. The source is a random partially polarizedbeam of light obeying Gaussian statistics and the image quality is evaluated as a function of the degree of polarization (DoP). We show that the visibility improves when the DoP and the order of imaging increase, while the SNR behaves oppositely. The CNR is for the most part independent of DoP and the imaging order. The results are important for the development of new imaging devices using partially polarizedlight.

Within the framework of further development of unified Monte Carlo code for the needs of biomedical optics and biophotonics, we present an approach for modeling of coherent polarizedlight propagation in highly scattering turbid media, such as biological tissues. The temporal coherence of light, linear and circular polarization, interference, and the helicity flip of circularly polarizedlight due to reflection at the medium boundary and/or backscattering events are taken into account. To achieve higher accuracy in the results and to speed up the modeling, the implementation of the code utilizes parallel computing on NVIDIA graphics processing units using Compute Unified Device Architecture. The results of the simulation of coherent linearly and circularly polarizedlight are presented in comparison with the results of known theoretical studies and the results of alternative modelings.

Cephalopods (squid, cuttlefish and octopus) are probably best known for their ability to change color and pattern for camouflage and communication. This is made possible by their complex skin, which contains pigmented chromatophore organs and structural light reflectors (iridophores and leucophores). Iridophores create colorful and linearly polarized reflective patterns. Equally interesting, the photoreceptors of cephalopod eyes are arranged in a way to give these animals the ability to detect the linear polarization of incoming light. The capacity to detect polarizedlight may have a variety of functions, such as prey detection, navigation, orientation and contrast enhancement. Because the skin of cephalopods can produce polarized reflective patterns, it has been postulated that cephalopods could communicate intraspecifically through this visual system. The term 'hidden' or 'private' communication channel has been given to this concept because many cephalopod predators may not be able to see their polarized reflective patterns. We review the evidence for polarization vision as well as polarization signaling in some cephalopod species and provide examples that tend to support the notion--currently unproven--that some cephalopods communicate using polarizedlight signals.

This chapter describes the usage of polarization features of visible light for automatic landmine detection. The first section gives an introduction to land-mine detection and the usage of camera systems. In section 2 detection concepts and methods that use polarization features are described. Secti

It is shown that multiple scattering of polarizedlight in a turbid medium can be represented as independent propagation of three basic modes: intensity and linearly and circularly polarized modes. Weak interaction between the basic modes can be described by perturbation theory and gives rise to "ov

This is a single scene from a pair (frames 021 and 024) to study the effects of polarizedlight in Earth Observations. One scene was exposed with vertically polarizedlight, the other, horizontally. The subject in this study, is a lake behind Presa (dam) Don Martin (27.5N, 100.5W) on the edge of the Rio Grande Plain near it's boundry with the Sierra Madre Orientral in Coahuila, Mexico.

This is a single scene from a pair (frames 021 and 024) to study the effects of polarizedlight in Earth Observations. One scene was exposed with vertically polarizedlight, the other, horizontally. The subject in this study, is a lake behind Presa (dam) Don Martin (27.5N, 100.5W) on the edge of the Rio Grande Plain near it's boundry with the Sierra Madre Orientral in Coahuila, Mexico.

Neglecting polarizedlight as an adjuvant therapy for pressure ulcers and methodology distinctions in the trials engaging polarizedlight are the reasons for many dilemmas and contradictions. The aim of this study was to establish the effects of polarizedlight therapy in pressure ulcer healing. This prospective randomized single-blind study involved 40 patients with stage I-III of pressure ulcer. The patients in the experimental group (E) were subjected, besides polarizedlight therapy, to standard wound cleaning and dressing. Standard wound cleaning and dressing were the only treatment used in the control group (C). A polarizedlight source was a Bioptron lamp. Polarizedlight therapy was applied for six min daily, five times a week, four weeks. The Pressure Ulcer Scale for Healing (PUSH) was used in the assessment of outcome. Statistic analysis included Mann Whitney Test, Fisher Exact Test, Wilcoxon Signed Rank test. There were significant differences between the groups at the end of the treatment regarding the surface of pressure ulcer (E: 10.80 +/- 19.18; C: 22,97 +/- 25,47; p = 0.0005), rank of pressure ulcer (E: 5.90 +/- 2.48; C: 8.6 +/- 1.05; p = 0.0005) and total PUSH score (E: 7.35 +/- 3.17; C: 11.85 +/- 2.35; p = 0,0003). The patients in the experimental group had significantly better values of the parameters monitored than the patients in the control group. After a four-week polarizedlight therapy 20 patients with stage I-III ulcer had significant improvement in pressure ulcer healing, so it could be useful to apply polarizedlight in the treatment of pressure ulcers.

Full Text Available Background/Aim. Neglecting polarizedlight as an adjuvant therapy for pressure ulcers and methodology distinctions in the trials engaging polarizedlight are the reasons for many dilemmas and contradictions. The aim of this study was to establish the effects of polarizedlight therapy in pressure ulcer healing. Methods. This prospective randomized single-blind study involved 40 patients with stage I-III of pressure ulcer. The patients in the experimental group (E were subjected, besides polarizedlight therapy, to standard wound cleaning and dressing. Standard wound cleaning and dressing were the only treatment used in the control group (C. A polarizedlight source was a Bioptron lamp. Polarizedlight therapy was applied for six min daily, five times a week, four weeks. The Pressure Ulcer Scale for Healing (PUSH was used in the assessment of outcome. Statistic analysis included Mann Whitney Test, Fisher Exact Test, Wilcoxon Signed Rank test. Results. There were significant differences between the groups at the end of the treatment regarding the surface of pressure ulcer (E: 10.80±19.18; C: 22,97±25,47; p = 0.0005, rank of pressure ulcer (E: 5.90±2.48; C: 8.6±1.05; p = 0.0005 and total PUSH score (E: 7.35±3.17; C: 11.85±2.35; p = 0,0003. The patients in the experimental group had significantly better values of the parameters monitored than the patients in the control group. Conclusion. After a four-week polarizedlight therapy 20 patients with stage I-III ulcer had significant improvement in pressure ulcer healing, so it could be useful to apply polarizedlight in the treatment of pressure ulcers.

Laser direct-writing is an important technique for the fabrication of complex patterns. There is a continuous need for structures with increasingly small features, i.e., enhanced resolution. Focused radially polarizedlight is known to exhibit a narrow longitudinal polarization component. Here, a proof-of-concept is shown of enhanced resolution through polarization-selectivity by the selective recording of the longitudinal polarization component in a polarization-selective homeotropic and smectic B photoresist. The full-width-at-half-maximum (FWHM) of the fabricated spots in the polarization-selective resist is up to 56% smaller compared to the FWHM of the same spot in a photoresist that is not polarization-selective, which supports simulations that predict a theoretical maximum reduction of 62%.

Measurements of the upwelling polarized radiance in relatively shallow waters of varying depths and benthic conditions are compared to simulationsrevealing the depolarizing nature of the seafloor. Significant correlations between simulations and measurements are attained when the appropriate unpolarized, Lambertian bottoms are included in the radiative transfer model. The bottoms used in this study produce realistic upwelling radiance distributions as well as ranges of the degree of linear polarization (DoLP) that peak between 10 and 30%. This study specifically finds that polarization in upwelling radiance is best preserved at long wavelengths in clear waters and also at short wavelengths in phytoplankton- and CDOM-rich waters. These results can thus facilitate the detection of benthic materials as well as future studies of camouflage by benthic biota.The DoLPwas found to be highly sensitive to benthic reflectance, but the angle of polarization (AoLP), which quantifies the orientation of polarization, is independent of it. The AoLP could therefore be used to communicate and sense direction underwater.

Nonlinear QED interactions induce different polarization properties on a given probe beam. We consider the polarization effects caused by the photon-photon interaction in laser experiments, when a laser beam propagates through a constant magnetic field or collides with another laser beam. We solve the quantum Boltzmann equation within the framework of the Euler-Heisenberg Lagrangian for both time-dependent and constant background field to explore the time evolution of the Stokes parameters Q, U, and V describing polarization. Assuming an initially linearly polarized probe laser beam, we also calculate the induced ellipticity and rotation of the polarization plane.

We describe the polarization topology of the vector beams emerging from a patterned birefringent liquid crystal plate with a topological charge $q$ at its center ($q$-plate). The polarization topological structures for different $q$-plates and different input polarization states have been studied experimentally by measuring the Stokes parameters point-by-point in the beam transverse plane. Furthermore, we used a tuned $q=1/2$-plate to generate cylindrical vector beams with radial or azimuthal polarizations, with the possibility of switching dynamically between these two cases by simply changing the linear polarization of the input beam.

We describe the polarization topology of the vector beams emerging from a patterned birefringent liquid crystal plate with a topological charge q at its center (q-plate). The polarization topological structures for different q-plates and different input polarization states have been studied experimentally by measuring the Stokes parameters point-by-point in the beam transverse plane. Furthermore, we used a tuned q=1/2-plate to generate cylindrical vector beams with radial or azimuthal polarizations, with the possibility of switching dynamically between these two cases by simply changing the linear polarization of the input beam.

When polarized electrons traverse a region where the laser light is focused their polarization varies even if their energy and direction of motion are not changed. This effect is due to interference of the incoming electron wave and an electron wave scattered at zero angle. Equations are obtained which determine the variation of the electron-density matrix, and their solutions are given. The change in the electron polarization depends not only on the Compton cross section but on the real part of the forward Compton amplitude as well. It should be taken into account, for example, in simulations of the e{yields}{gamma} conversion for future {gamma}{gamma} colliders. (orig.). 16 refs.

We propose a new phototherapy using polarizedlight from light emitting diode (LED). The purpose of this study is to clarify the effect of polarized LED irradiation on wound healing. Five groups were classified: control (C), unpolarized (U), linearly polarized (L), right circularly polarized (RC), and left circularly polarized (LC) LED irradiation. In vitro study, fibroblast cell cultures were irradiated, and cellular proliferation was evaluated with a WST-8 assay. In vivo study, full-thickness skin defect of 20 mm diameter was created on the dorsal side of rats. The ratio of the residual wound area was measured, and expression of type 1 and type 3 procollagen mRNA in granulation tissue was determined by real-time reverse transcription polymerase chain reaction method. The cellular proliferation rates of group RC and L were significantly higher than other groups. The ratio of the residual wound area of group RC and L was significantly reduced than group C and U. Expression of type 1 procollagen mRNA in group RC was found to be significantly increased about 1.5-fold in comparison with the group C. There were no significant differences for type 3 procollagen. The right circularly polarizedlight and linearly polarizedlight promoted the process of wound healing by increasing the proliferation of fibroblasts, and the right circularly polarizedlight increased the expression of type 1 procollagen mRNA. The effectiveness of right circularly polarizedlight suggests that some optical active material, which has a circular dichroic spectrum, takes part in a biochemical reaction.

Optical transmission through concentric circular nanoslits is studied in experiments and numerical simulations. Polarized optical microscopic imaging shows that the optical transmission through these apertures is spatially inhomogeneous, exhibiting colored fan texture patterns. Numerical simulations show that these colored fan texture patterns originate from the cylindrical vector polarization of the transmitted beam. Specifically, the transmitted light is in-phase radially polarized at long wavelengths due to the predominant transmission of the transverse magnetic (TM) waveguide modes; and in-phase azimuthally polarized at short wavelengths due to the increased optical transmission of the transverse electric (TE) waveguide modes. Additionally, the transmission shows a peak at the wavelength of Wood anomaly and a dip at the resonant wavelength of surface plasmon excitation; and the transmitted light at these wavelengths is a mixture of azimuthally and radially polarized fields. These interesting optical transmission behaviors of circular nanoslits provide a miniaturized way to generating radially and azimuthally polarizedlight.

Neutron Zeeman spatial beam-splitting is considered at reflection from magnetically noncollinear films. Two applications of Zeeman beam-splitting phenomenon in polarized neutron reflectometry are discussed. One is the construction of polarizing devices with high polarizing efficiency. Another one is the investigations of magnetically noncollinear films with low spin-flip probability. Experimental results are presented for illustration.

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

Installing Siberian snakes in a circular proton accelerator allows one to overcome all spin depolarizing resonances even at very high energies. However, Siberian snake application at low energies is technically rather difficult. Turning snake on at some energy during acceleration would allow using Siberian snakes even in rings with low injection energies. It is shown that the beampolarization would be preserved during the snake ramp, provided that the snake is turned on in more than ten turns, and the energy is set near a half-integer G gamma.

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization, but full Siberian snakes cause intolerably large orbit excursions. Using a 20 - 30 % partial Siberian snake, both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical super-conducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

Describes a method for identifying and examining single ice crystals by photographing a thin sheet of ice placed between two inexpensive polarizing filters. Suggests various natural and prepared sources for ice that promote students' insight into crystal structures, and yield colorful optical displays. Includes directions, precautions, and sample…

We recall the framework of a consistent quantum description of polarization of light. Accordingly, the degree of polarization of a two-mode state $\\hat \\rho$ of the quantum radiation field can be defined as a distance of a related state ${\\hat \\rho}_b$ to the convex set of all SU(2) invariant two-mode states. We explore a distance-type polarization measure in terms of the quantum Chernoff bound and derive its explicit expression. A comparison between the Chernoff and Bures degrees of polarization leads to interesting conclusions for some particular states chosen as illustrative examples.

The wave equation of lightbeam propagation was written in the form of an axial-coordinate-dependent Schrodinger equation, and the expectation value of a dynamical variable, the trial function of variational approach and the ABCD law were discussed by use of quantum mechanics approach. In view of the evolution equations of expectation values of dynamical variables in the framework of quantum mechanics, the definition of a potential function representing the beam propagation stability and its universal formula with the quality factor, the universal formula of beam width and curvature radius for a paraxial beam and cylindrically symmetric non-paraxial beam, the general formula of second derivative of beam width with respect to the axial coordinate of beam for a paraxial beam, and the general criteria of the conservation of beam quality factor and the existence of a potential well of a potential function for a paraxial beam, were given or derived, respectively. Starting with the same trial function, the co

The stability of a light sail riding on a laser beam is analyzed both analytically and numerically. Conical sails on Gaussian beams, which have been studied in the past, are shown to be unstable in general. A new architecture for a passively stable sail and beam configuration is proposed. The novel spherical shell sail design is capable of "beam riding" without the need for active feedback control. Full three-dimensional ray-tracing simulations are performed to verify our analytical results.

The performance of the knife-edge method as a beam profiling technique for tightly focused lightbeams depends on several parameters, such as the material and height of the knife-pad as well as the polarization and wavelength of the focused lightbeam under study. Here we demonstrate that the choice of the substrate the knife-pads are fabricated on has a crucial influence on the reconstructed beam projections as well. We employ an analytical model for the interaction of the knife-pad with the beam and report good agreement between our numerical and experimental results. Moreover, we simplify the analytical model and demonstrate, in which way the underlying physical effects lead to the apparent polarization dependent beam shifts and changes of the beamwidth for different substrate materials and heights of the knife-pad.

Numerical methods, using rigorous coupled wave theory, are used to design rectangular relief diffraction gratings for an infrared application which requires comparable first order efficiencies in the TE and TM polarization states. The depth, period, and fill factor of the grating are varied to identify optimal two level binary lamellar grating profiles which predict efficiencies for individual TM and TE polarizations above 75 percent, while keeping the difference between the two efficiencies within 10 percent. The application at hand is a rotating, transmissive diffractive scanner for space-based coherent lidar. The operating wavelength is 2.0 microns. A collimated, circularly polarizedbeam is incident on the diffractive scanner at the Bragg angle; 30 and 45 degree beam deflection angles being studied. Fused silica is the substrate material of choice. Selected designs are fabricated on 3 inch fused silica substrates using lithographic methods. The performance of the test pieces is measured and compared to theoretical predictions.

A discontinuous space variant sub-wavelength dielectric grating is designed and fabricated for generating radially polarizedlight in visible region (l = 632.8 nm). The design is based on sub-wavelength silicon nitride structures introducing a retardation of p/2 by form birefringence, with space variant orientation of the optical axis. The pattern is divided into concentric ring segments with constant structural parameters, therefore reducing electron-beam writing time significantly. The design avoids the technological challenges encountered in the generation of a continuous space variant grating while maintaining good quality of the resulting polarization mode.

We present a detailed theoretical analysis of the formation of standing waves using cylindrically polarized vector Laguerre-Gaussian (LG) beams. It is shown that complex interplay between the radial and azimuthal polarization state can be used to realize different kinds of polarization gradients with cylindrically symmetric polarization distribution. Expressions for four different cases are presented and local dynamics of spatial polarization distribution is studied. We show cylindrically symmetric Sisyphus and corkscrew type polarization gradients can be obtained from vector LG beams. The optical landscape presented here with spatially periodic polarization patterns may find important applications in the field of atom optics, atom interferometry, atom lithography, and optical trapping.

The electric charge accumulation under an electron beam irradiation (40 keV and 60 keV) was measured by using the pressure wave propagation (PWP) method in the dielectric insulation materials, such as polar polymeric films (polycarbonate (PC), polyethylene-naphthalate (PEN), polyimide (PI), and polyethylene-terephthalate (PET)) and non-polar polymeric films (polystyrene (PS), polypropylene (PP), polyethylene (PE) and polytetrafluoroethylene (PTFE)). The PE and PTFE (non-polar polymers) showed the properties of large amount of electric charge accumulation over 50 C/m3 and long saturation time over 80 minutes. The PP and PS (non-polar polymer) showed the properties of middle amount of charge accumulation about 20 C/m3 and middle saturation time about 1 to 20 minutes. The PC, PEN, PI and PET (polar polymers) showed the properties of small amount of charge accumulation about 5 to 20 C/m3 and within short saturation time about 1.0 minutes. This paper summarizes the relationship between the properties of charge accumulation and chemical structural formula, and compares between the electro static potential distribution with negative charged polymer and its chemical structural formula.

Optical limiting (OL) effects can be enhanced by exploiting various limiting mechanisms and by designing nonlinear optical materials. In this work, we present the large enhancement of OL effects by manipulating the polarization distribution of the light field. Theoretically, we develop the Z-scan and nonlinear transmission theories on a two-photon absorber under the excitation of cylindrical vector beams. It is shown that both the sensitivity of Z-scan technique and the OL effect using radially polarizedbeams have the large enhancement compared with that using linearly polarizedbeams (LPBs). Experimentally, we investigate the nonlinear absorption properties of a double-decker Pr[Pc(OC{sub 8}H{sub 17}){sub 8}]{sub 2} rare earth complex by performing Z-scan measurements with femtosecond-pulsed radially polarizedbeams at 800 nm wavelength. The observed two-photon absorption process, which originates from strong intramolecular π–π interaction, is exploited for OL application. The results demonstrate the large enhancement of OL effects using radially polarizedbeams instead of LPBs.

Linearly polarized (LP) and unpolarized (UP) light are racemic entities since they can be described as superposition of opposite circularly polarized (CP) components of equal amplitude. As a consequence they do not carry spin angular momentum. Chiral resolution of a racemate, i.e. separation of their chiral components, is usually performed via asymmetric interaction with a chiral entity. In this paper we provide an experimental evidence of the chiral resolution of linearly polarized and unpolarized Gaussian beams through the transfer of spin angular momentum to chiral microparticles. Due to the interplay between linear and angular momentum exchange, basic manipulation tasks, as trapping, spinning or orbiting of micro-objects, can be performed by light with zero helicity. The results might broaden the perspectives for development of miniaturized and cost-effective devices.

We explore the possibility to control the polarization state of light confined into sub-diffraction volumes by means of plasmonic optical antennas. To this aim, we describe a resonant cross antenna, constituted of two perpendicular two-wire antennas sharing the same gap, which is able to maintain the polarization state in the plane of the antenna. We also discuss how, by proper tuning of the arm length in a slightly off-resonance cross antenna, it is possible to effectively realize a nanoscale quarter-waveplate antenna. We present experimental results for the preparation of individual cross antennas by means of focused ion beam milling starting from single-crystalline Au microflakes, and finally show preliminary characterization results based on two-photon photoluminescence confocal imaging with linearly-polarizedlight.

@@ We propose and analyze a novel ultra-compact polarizationbeam splitter based on a resonator cavity in a two-dimensional photonic crystal.The two polarizations can be separated efficientlyby the strong coupling between the microcavities and the waveguides occurring around the resonant frequency of the cavities.The transmittance of two polarizedlight around 1.55 iim can be more than 98.6%, and the size of the device is less than 15 μm x 13μm,so these features will play an important role in future integrated optical circuits.

This study introduces an efficient polarized, white phosphor-converted, light-emitting diode (pc-LED) using a remote phosphor film sandwiched between a reflective polarizer film (RPF) and a short-wavelength pass dichroic filter (SPDF). The on-axis brightness of polarized white light emission of a RPF/SPDF-sandwiched phosphor film over a blue LED, showed greater recovery than that of a conventional unpolarized remote phosphor film over blue LED, due to the recycling effect of yellow light from an SPDF. The relative luminous efficacy of an RPF/SPDF-sandwiched phosphor film was made 1.40 times better by adding an SPDF on the backside of an RPF-capped phosphor film. A polarization ratio of 0.84 was demonstrated for a white LED with an RPF/SPDF-sandwiched phosphor film, in good agreement with the measured results from the RPF-only sample.

An unpolarized normal-incidence lightbeam reflected by a cholesteric liquid crystal is left- or right-circularly polarized, in the cholesteric temperature range. In this article, we present a novel approach for fabricating a cholesteric liquid crystalline material that exhibits reflection bands with both senses of polarization at room temperature. A cholesteric liquid crystal that presents a twist inversion at a critical temperature T(c) is blended with a small quantity of photopolymerizable monomers. Upon ultraviolet irradiation above T(c), the liquid crystal becomes a polymer-stabilized liquid crystal. Below T(c), the material reflects a dual circularly polarized band in the infrared. By quenching the experimental cell at a temperature below the blend's melting point, the optical properties of the material in an undercooled state are conserved for months at room temperature, which is critical to potential applications such as heat-repelling windows and polarization-independent photonic devices.

Full Text Available Circularly polarizedlight, rare in the animal kingdom, has thus far been documented in only a handful of animals. Using a rotating circular polarization (CP analyzer we detected CP in linearly polarizedlight transmitted through epipelagic free living Sapphirina metallina copepods. Both left and right handedness of CP was detected, generated from specific organs of the animal's body, especially on the dorsal cephalosome and prosome. Such CP transmittance may be generated by phase retardance either in the muscle fibers or in the multilayer membrane structure found underneath the cuticle. Although the role, if any, played by circularly polarizedlight in Sapphirinidae has yet to be clarified, in other animals it was suggested to take part in mate choice, species recognition, and other forms of communication.Planktonic Sapphirinidae copepods were found to circularly polarize the light passing through them. Circular polarization may be created by unique, multilayered features of the membrane structure found under their cuticle or by organized muscle fibers.

Based on the vector angular spectrum representation of optical beam and the method of stationary phase, the analytical TE and TM terms of vector Gaussian beam have been presented in the far field. By using the local polarization matrix, the polarization properties of the TE and TM terms in the far field are investigated, and it is found that the degree of their polarization is only determined by the spatial location. When the source is completely polarized, the TE and TM terms are both completely polarized in the far field. When the source is completely unpolarized, the TE and TM terms in the far field are partially polarized. The whole beam is also partially polarized except on the propagating axis. Moreover, the degrees of polarization of TE and TM terms are both larger than that of the whole beam.

A spatially variable retardation device,an SQWP,is designed to generate polarization vortex beams.The transformation of Laguerre-Gaussian beams by the SQWP is further studied,and it is found that the SQWPs can also be used to generate helical beams and measure the topological charges of helical beams.

We report the development of an optical system based on diffractive optical elements and uniaxial crystals to produce radially and azimuthally polarizedbeams, including beams of higher orders. The conditions for the generation of beams with different polarization states in an anisotropic crystal with an arbitrary axially symmetric amplitude distribution are analyzed theoretically. The results of the experimental study on the generation of cylindrical vector beams in a calcite crystal agree with the results of the simulation.

To obtain highly nuclear-spin vector polarized negative deuterium ion beam, a dual optically pumped polarized negative deuterium ion source has been developed at KEK. It is possible to select a pure nuclear-spin state with this scheme, and negative deuterium ion beam with 100% nuclear-spin vector polarization can be produced in principle. We have obtained about 70% of nuclear-spin vector polarized negative deuterium ion beam so far. This result may open up a new possibilities for the optically pumped polarized ion source. (author)

A polarizationbeam splitter based on a self-collimation Michelson interferometer (SMI) in a hole-type silicon photonic crystal is proposed and numerically demonstrated.Utilizing the polarization dependence of the transmission spectra of the SMI and polarization peak matching method,the SMI can work as a polarizationbeam splitter (PBS) by selecting an appropriate path length difference in the structure.Based on its novel polarizationbeam splitting mechanics,the polarization extinction ratios (PERs) for TM and TE modes are as high as 18.4 dB and 24.3 dB,respectively.Since its dimensions are only several operating wavelengths,the PBS may have practical applications in photonic integrated circuits.%A polarizationbeam splitter based on a self-collimation Michelson interferometer (SMI) in a hole-type silicon photonic crystal is proposed and numerically demonstrated. Utilizing the polarization dependence of the transmission spectra of the SMI and polarization peak matching method, the SMI can work as a polarizationbeam splitter (PBS) by selecting an appropriate path length difference in the structure. Based on its novel polarizationbeam splitting mechanics, the polarization extinction ratios (PERs) for TM and TE modes are as high as 18.4 dB and 24.3 dB, respectively. Since its dimensions are only several operating wavelengths, the PBS may have practical applications in photonic integrated circuits.

This proposal is for the development of a computational model of a prototype variable beamlight source using optical modeling software, Zemax Optics Studio. The variable beamlight source would be designed to generate flood, spot, and directional beam patterns, while maintaining the same average power usage. The optical model would demonstrate the possibility of such a light source and its ability to address several issues: commonality of design, human task variability, and light source design process improvements. An adaptive lighting solution that utilizes the same electronics footprint and power constraints while addressing variability of lighting needed for the range of exploration tasks can save costs and allow for the development of common avionics for lighting controls.

The use of beampolarization at the future ILC e{sup +}e{sup -} linear collider will benefit the physics program significantly. This thesis explores three aspects of beampolarization: the application of beampolarization to the study of electroweak processes, the precise measurement of the beampolarization, and finally, the production of polarized positrons at a test beam experiment. In the first part of the thesis the importance of beampolarization at the future ILC is exhibited: the benefits of employing transverse beampolarization (in both beams) for the measurement of triple gauge boson couplings (TGCs) in the W-pair production process are studied. The sensitivity to anomalous TGC values is compared for the cases of transverse and longitudinal beampolarization at a center of mass energy of 500 GeV. Due to the suppressed contribution of the t-channel {nu} exchange, the sensitivity is higher for longitudinal polarization. For some physics analyses the usual polarimetry techniques do not provide the required accuracy for the measurement of the beampolarization (around 0.25% with Compton polarimetry). The second part of the thesis deals with a complementary method to measure the beampolarization employing physics data acquired with two polarization modes. The process of single-W production is chosen due to its high cross section. The expected precision for 500 fb{sup -1} and W{yields}{mu}{nu} decays only, is {delta}P{sub e{sup -}}/P{sub e{sup -}}=0.26% and {delta}P{sub e{sup +}}/P{sub e{sup +}}=0.33%, which can be further improved by employing additional W-decay channels. The first results of an attempt to produce polarized positrons at the E-166 experiment are shown in the last part of the thesis. The E-166 experiment, located at the Final Focus Test Beam at SLAC's LINAC employs a helical undulator to induce the emission of circularly polarized gamma rays by the beam electrons. These gamma rays are converted into longitudinally polarized electron

By means of a pair of boresighted and synchronized cameras fitted with orthogonally oriented polarizing filters and carried aboard the Space Shuttle, a large number of polarized images of the earth's surface have been obtained from orbital altitude. Selected pairs of images, both in color and in black and white, have been digitized and computer-processed to yield analogous images in each of the three Stokes parameters necessary for characterizing the state of linear polarization of the emergent light. Many of the images show surface properties more distinctly in degree and plane of polarization than in simple intensity alone. It is believed that these are the first, and certainly the most extensive, set of polarized images of the earth ever obtained from space. Selected pairs of the images are presented here along with some early results of analysis.

While it is generally accepted that honeybees (Apis mellifera) are capable of using the pattern of polarizedlight in the sky to navigate to a food source, there is little or no direct behavioural evidence that they actually do so. We have examined whether bees can be trained to find their way through a maze composed of four interconnected tunnels, by using directional information provided by polarizedlight illumination from the ceilings of the tunnels. The results show that bees can learn this task, thus demonstrating directly, and for the first time, that bees are indeed capable of using the polarized-light information in the sky as a compass to steer their way to a food source.

Using polarization measurements, the reflectance factor of two wheat canopies is divided into components due to specularly and diffusely reflected light. The data show that two key angles may be predicted, the angle of the polarizer for minimum flux and the angle of incidence of sunlight specularly reflected by a leaf to a sensor. The results show that specular reflection is a key aspect to radiation transfer by two canopies. Results suggest that the advent of heading in wheat may be remotely sensed from polarization measurements of the canopy reflectance.

In this paper a compact polarizationbeam splitter based on a deformed photonic crystal directional coupler is designed and simulated. The transverse-electric (TE) guided mode and transverse-magnetic (TM) guided mode are split due to different guiding mechanisms. The effect of the shape deformation of the air holes on the coupler is studied. It discovered that the coupling strength of the coupled wavegnides is strongly enhanced by introducing elliptical airholes, which reduce the device length to less than 18.5μm. A finite-difference time-domain simulation is performed to evaluate the performance of the device, and the extinction ratios for both TE and TM polarizedlight are higher than 20 dB.

Meta-surfaces are planar structures that locally change polarization, phase, and amplitude of light, thus enabling flat, lithographically patterned free-space optical components with functionalities controlled by design. Several types of meta-surfaces have been reported, but low efficiency and the inability to provide simultaneous phase and polarization control have limited their applications. Here we demonstrate a platform based on high-contrast dielectric elliptical nano-posts providing complete and efficient control of polarization and phase with sub-wavelength spatial resolution. The unprecedented freedom in manipulating light not only enables realization of conventional free-space transmissive optical elements such as phase-plates, wave-plates and beam-splitters, but also elements with novel functionalities such as general polarization switchable phase holograms and arbitrary vector beam generators which will change the design paradigms for free-space optical systems.

A cold neutron beam at the ILL High Flux Reactor was used to produce highly polarized neutrons by means of a bent supermirror polarizer. A following current sheet spin flipper allowed the change of the neutron spin direction relative to the guiding magnetic fields. The degree of polarization of the beam was measured as a function of the neutron velocity in the range 300-1500 m/s achieving an accuracy of 0.2% at typically 98% polarization. Two spin flippers and the permutation of three supermirror polarizers as polarizer/analyzer were employed. (orig.).

This article presents a clinical investigation of polarizedlight therapy after aesthetic surgery procedures. The study included patients who the authors underwent face-lifts, blepharoplasties, and various facial ancillary procedures, at center during the past 2 1/2 years. One side of the surgically treated area was managed with polarizedlight, whereas the other side served as a control. The results were compared using clinical examination only including signs of recovery such as resolution of swelling and bruises. The results in most cases showed a significant difference between the treated and untreated sides.

A beam profile monitor utilizing visible synchrotron radiation (SR) from a bending magnet has been designed and installed in Cornell Electron-Positron Storage Ring (CESR). The monitor employs a double-slit interferometer to measure both the horizontal and vertical beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 μm can be measured with a resolution of approximately 5 μm. To measure larger beam size (>500 μm), direct imaging can be employed by rotating the double slits away from SR beam path. By imaging the π-polarized component of SR, a small vertical beam size (∼70 μm) was measured during an undulator test run in CESR, which was consistent with the interferometer measurement. To measure the bunch length, a beam splitter is inserted to direct a fraction of light into a streak camera setup. This beam size monitor measures the transverse and longitudinal beam sizes simultaneously, which is successfully used for intrabeam scattering studies. Detailed error analysis is discussed.

In order to obtain the means to control lightpolarization, we designed a structure of coupled magnetic resonators and studied its transmission properties by the 4 x 4 transfer matrix method. The incidence of linearly polarizedlight results in two transmission resonant peaks of left-handed circular polarization at shorter wavelengths and two transmission resonant peaks of right-handed circular polarization at longer wavelengths, respectively. Through adjusting the magnetizations, the inner left-handed circular polarization and right-handed circular polarization can be merged into one linear polarization, while the two outside resonant peaks keep their circular polarization. The polarized direction of the output linearly polarizedlight can be controlled by the polarized direction of incidence light. The incidence light with one polarization can output light with three kinds of polarizations through the designed structure. (orig.)

The FCC-ee accelerator is considered within the FCC design study as a possible first step towards the ultimate goal of a 100 TeV hadron collider. It is a high luminosity e+e- storage ring collider, designed to cover energies of around 90, 160, 240 and 350GeV ECM (for the Z peak, the WW threshold, the ZH and ttbar cross-section maxima respectively) leading to different operating modes. We report on the current status of the design study, on the most promising concepts and relevant challenges. The expected luminosity performance at all energies, and first studies on transverse polarization for beam energy calibrations will be presented.

If the recent PVLAS results on polarization changes of a linearly polarized laser beam passing through a magnetic field are interpreted by an axion-like particle, it is almost certain that it is not a standard QCD axion. Considering this, we study the general effective interactions of photons with spin-zero particles without restricting the latter to be a pseudo-scalar or a scalar, i.e., a parity eigenstate. At the lowest order in effective field theory, there are two dimension-5 interactions, each of which has previously been treated separately for a pseudo-scalar or a scalar particle. By following the evolution in an external magnetic field of the system of spin-zero particles and photons, we compute the changes in lightpolarization and the transition probability for two experimental set-ups: one-way propagation and round-trip propagation. While the first may be relevant for astrophysical sources of spin-zero particles, the second applies to laboratory optical experiments like PVLAS. In the one-way propagation, interesting phenomena can occur for special configurations of polarization where, for instance, transition occurs but lightpolarization does not change. For the round-trip propagation, however, the standard results of polarization changes for a pseudoscalar or a scalar are only modified by a factor that depends on the relative strength of the two interactions.

We propose the design of a space-variant Wien filter for electron beams that induces a spin half-turn and converts the corresponding spin angular momentum variation into orbital angular momentum of the beam itself by exploiting a geometrical phase arising in the spin manipulation. When applied to a spatially coherent input spin-polarized electron beam, such a device can generate an electron vortex beam, carrying orbital angular momentum. When applied to an unpolarized input beam, the proposed device, in combination with a suitable diffraction element, can act as a very effective spin-polarization filter. The same approach can also be applied to neutron or atom beams.

Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarizedbeams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of ⩾200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while ⩾500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns.

treatment volume compared to those in conventional (photon) treatments. Wilson wrote his personal account of this pioneering work in 1997. In 1954 Cornelius Tobias and John Lawrence at the Radiation Laboratory (former E.O. Lawrence Berkeley National Laboratory) of the University of California, Berkeley performed the first therapeutic exposure of human patients to hadron (deuteron and helium ion) beams at the 184-Inch Synchrocyclotron. By 1984, or 30 years after the first proton treatment at Berkeley, programs of proton radiation treatments had opened at: University of Uppsala, Sweden, 1957; the Massachusetts General Hospital-Harvard Cyclotron Laboratory (MGH/HCL), USA, 1961; Dubna (1967), Moscow (1969) and St Petersburg (1975) in Russia; Chiba (1979) and Tsukuba (1983) in Japan; and Villigen, Switzerland, 1984. These centers used the accelerators originally constructed for nuclear physics research. The experience at these centers has confirmed the efficacy of protons and light ions in increasing the tumor dose relative to normal tissue dose, with significant improvements in local control and patient survival for several tumor sites. M.R. Raju reviewed the early clinical studies. In 1990, the Loma Linda University Medical Center in California heralded in the age of dedicated medical accelerators when it commissioned its proton therapy facility with a 250-MeV synchrotron. Since then there has been a relatively rapid increase in the number of hospital-based proton treatment centers around the world, and by 2006 there are more than a dozen commercially-built facilities in use, five new facilities under construction, and more in planning stages. In the 1950s larger synchrotrons were built in the GeV region at Brookhaven (3-GeV Cosmotron) and at Berkeley (6-GeV Bevatron), and today most of the world's largest accelerators are synchrotrons. With advances in accelerator design in the early 1970s, synchrotrons at Berkeley and Princeton accelerated ions with atomic numbers

We report, in theory and experiment, on a novel class of controlled light capsules with nearly perfect darkness, directly employing intrinsic properties of modified Bessel-Gauss beams. These beams are able to naturally create three-dimensional bottle-shaped region during propagation as long as the parameters are properly chosen. Remarkably, the optical bottle can be controlled to demonstrate various geometries through tuning the beam parameters, thereby leading to an adjustable light capsule. We provide a detailed insight into the theoretical origin and characteristics of the light capsule derived from modified Bessel-Gauss beams. Moreover, a binary digital micromirror device (DMD) based scheme is first employed to shape the bottle beams by precise amplitude and phase manipulation. Further, we demonstrate their ability for optical trapping of core-shell magnetic microparticles, which play a particular role in biomedical research, with holographic optical tweezers. Therefore, our observations provide a new rou...

This study aimed to determine the effect of active warm-up by local muscle light exercise and passive warm-up by polarizedlight irradiation on skin and muscle temperatures and forearm muscle performance (muscle strength, power, endurance, and controlled force-exertion). Ten healthy males performed various grip tests before and after active (local muscle light exercise) and passive (linear polarized near-infrared light irradiation) warm-ups. An active warm-up involved intermittent gripping exercise (contraction: 1 second and relaxation: 1 second) for 10 minutes using a sponge. A passive warm-up consisted of polarizedlight irradiation to the forearm (superficial digital flexor) for 10 minutes (irradiation: 5 seconds and rest: 1 second). Skin and muscle temperatures were measured during both warm-ups. Skin and muscle temperatures increased significantly after 5 minutes of local muscle light exercise and after 10 minutes of polarizedlight irradiation. Temperatures were significantly higher after 6 minutes of local muscle light exercise than after 6 minutes of polarizedlight irradiation. There were no significant differences of muscle strength, power, and controlled force-exertion before and after either warm-up. Average force outputs in all conditions significantly decreased with exertion time, and at 30, 60, 90, and 120 seconds they were higher in both warm-up conditions than in the non-warm-up condition. In conclusion, both warm-ups may contribute to improve muscle endurance performance in the decreasing force phase.

We numerically investigate the spatiotemporal structure of Bessel beams generated with spatial light modulators (SLMs). Grating-like phase masks enable the spatial filtering of undesired diffraction orders produced by SLMs. Pulse front tilt and temporal broadening effects are investigated. In addition, we explore the influence of phase wrapping and show that the spatiotemporal structure of SLM-generated femtosecond Bessel beams is similar to Bessel X-pulses at short propagation distance and to subluminal pulsed Bessel beams at long propagation distance.

Polarizedlight has been used as an aid in visualizing various skin conditions, including acne vulgaris, rosacea, photoageing, lentigo simplex, and basal cell carcinoma. The use of parallel-polarized and cross-polarizedlight was evaluated in mild irritant reactions to determine, if this increases the ability to detect very early stages or low levels of irritation. Low concentrations of sodium lauryl sulfate (0.01% and 0.1%) were patched on human volunteers for 2, 6, and 24 hr, daily for 2-3 days in a modification of the standard patch test. Feminine protection products were evaluated in the behind-the-knee (BTK) test. Erythema reactions were scored by unaided visual assessment and using a polarizedlight visualization system. In the 24-hr patch test, mean erythema assessed with polarizedlight was consistent with results of unaided visual scoring. Under milder conditions (2- and 6-hr patches), and in the BTK, significant differences from pretreatment levels of erythema were apparent earlier in the series of treatments compared with unaided scoring. In addition, subsurface scoring demonstrated that changes were still present under the skin surface even after unaided visual scoring indicated recovery. Low (subclinical) levels of irritation can be detected using enhanced visual scoring, indicating this non-invasive method has the potential to increase the sensitivity of our clinical studies.

Animals in the sea absorb, scatter, reflect, emit and sense underwater light. Large well developed eyes in most long range marine migrators suggest its navigational importance. Submarine lightpolarization may provide species that perceive it with a kind of sun compass even in deep water. Laboratory evidence has been found for compass card-like orientation to e-vector direction by both fishes and crustaceans.

The light's orbital angular momentum (OAM) is a consequence of the spiral flow of the electromagnetic energy. In this paper, an analysis of lightbeams with OAM used for free space optics (FSO) is conducted. The basic description and conception of light's OAM are reviewed. Both encoding information into OAM states of single lightbeam and encoding information into spatial structure of the mixed optical vortex with OAM are discussed, and feasibility to improve the FSO's performance of security and obstruction of line of sight is examined.

We have investigated the properties of TM polarizedlight in planar photonic crystal waveguide structures, which exhibit photonic band gaps for TE polarizedlight. Straight and bent photonic crystal waveguides and couplers have been fabricated in silicon-on-insulator material and modelled using a 3...... in a simple photonic crystal coupler with a size of ~ 20 m × 20 m. These promising features may open for the realization of ultra-compact photonic crystal components, which are easily integrated in optical communication networks....

The focusing of a radially polarizedbeam without annular apodization ora phase filter at the entrance pupil of the objective results in a wide focus and low purity of the longitudinally polarized component.However,the presence of a physical annular apodization or phase filter makes some applications more difficult or even impossible.We propose a radially polarized and amplitude-modulated annular multi-Gaussian beam mode.Numerical simulation shows that it can be focused into a sharper focal spot of 0.125λ2 without additional apodizations or filters.The beam quality describing the purity of longitudinally polarized component is up to 86％.

Originally an empirical law, nowadays Malus' law is seen as a key experiment to demonstrate the transverse nature of electromagnetic waves, as well as the intrinsic connection between optics and electromagnetism. In this work, a simple and inexpensive setup is proposed to quantitatively verify the nature of polarizedlight. A flat computer screen…

Polarizedlight applied to drilled laminated plastic components exposes to the human eye the locked-in stresses that will result in fractures and delaminations when the soldering procedure takes place. This technique detects stresses early in the production cycle before appreciable man-hours are invested in an item destined for rejection.

Space variant beams are of great importance as a variety of applications have emerged in recent years. As such, manipulation of their degrees of freedom is highly desired. Here, by exploiting the circular dichroism and circular birefringence in a Zeeman-shifted Rb medium, we study the general interaction of space variant beams with such a medium. We present two particular cases of radial polarization and hybrid polarizationbeams where the control of the polarization states is demonstrated experimentally. Moreover, we show that a Zeeman-shifted atomic system can be used as an analyzer for such space variant beams

The identification of a universal biosignature that could be sensed remotely is critical to the prospects for success in the search for life elsewhere in the universe. A candidate universal biosignature is homochirality, which is likely to be a generic property of all biochemical life. Due to the optical activity of chiral molecules, it has been hypothesized that this unique characteristic may provide a suitable remote sensing probe using circular polarization spectroscopy. Here, we report the detection of circular polarization in light scattered by photosynthetic microbes. We show that the circular polarization appears to arise from circular dichroism of the strong electronic transitions of photosynthetic absorption bands. We conclude that circular polarization spectroscopy could provide a powerful remote sensing technique for generic life searches.

SUMMARY The polarizedlight microscope reveals orientational order in native molecular structures inside living cells, tissues, and whole organisms. It is a powerful tool used to monitor and analyze the early developmental stages of organisms that lend themselves to microscopic observations. In this article, we briefly discuss the components specific to a traditional polarizing microscope and some historically important observations on: chromosome packing in the sperm head, the first zygote division of the sea urchin, and differentiation initiated by the first asymmetric cell division in the sand dollar. We then introduce the LC-PolScope and describe its use for measuring birefringence and polarized fluorescence in living cells and tissues. Applications range from the enucleation of mouse oocytes to analyzing the polarized fluorescence of the water strider acrosome. We end with new results on the birefringence of the developing chick brain, which we analyzed between developmental stages of days 12–20. PMID:23901032

A complete single-point statistical description of a narrow-band partially polarized optical field is developed in terms of the 2D period-averaged probability density function (PA-PDF) of the electrical field vector. This statistic can be measured using the coherent (heterodyne) detection. PA-PDF carries more information about the partially polarizedlight than the traditional Stokes vector. For a simple Gaussian partially polarized field the PA-PDF depends on 13 real parameters in contrast to the four parameters of the Stokes vector or coherence tensor. We show on several examples that the polarization state of the wave, as described by PA-PDF can vary significantly even while Stokes vector remains fixed.

In this study, we aimed to compare the polarity correction factor in ionization chambers for flattening filter free (FFF) photon beams and flattening filter (FF) beams. Measurements were performed with both 6 and 10 MV FFF and FF beams. Five commercial ionization chambers were evaluated: PTW TN30013; IBA Dosimetry CC01, CC04, and CC13; and Exradin A12S. Except for the CC01 ionization chamber, the other four chambers showed less than a 0.3 % difference in the polarity effect between the FFF and the FF beams. The CC01 chamber showed a strong field-size-dependence, unlike the other chambers. The polarity effect for all chambers with FFF beams did not change with the dose rate. Except in the case of the CC01 chamber, the difference in the polarity effect between FFF and FF beams was not significant.

A novel method of generation and synthesis of azimuthally E-polarized vortex beams is presented. Along the axis of propagation such beams have a strong longitudinally polarized magnetic field where ideally there is no electric field. We show how these beams can be constructed through the interference of Laguerre-Gaussian beams carrying orbital angular momentum. As an example, we present a metasurface made of double-split ring slot pairs and report a good agreement between simulated and analytical results. Both a high magnetic-to-electric-field contrast ratio and a magnetic field enhancement are achieved. We also investigate the metasurface physical constraints to convert a linearly polarizedbeam into an azimuthally E- polarizedbeam and characterize the performance of magnetic field enhancement and electric field suppression of a realistic metasurface. These findings are potentially useful for novel optical spectroscopy related to magnetic dipolar transitions and for optical manipulation of particles with sp...

There is increasing interest in cold heavy polar molecular species for their applications in fundamental physics, such as the tests of the electron’s electric dipole moment. Here we propose a switched ring Stark decelerator suitable for slowing both light and heavy polar molecules. Two typical polar molecular species, ND3 and 205TlF, are employed to test the feasibility of our scheme with the help of trajectory calculation. Our proposed scheme is found to share many advantages with the state-of-the-art traveling wave decelerator, yet with relatively simple electronics and flexible operation modes. Sub-millikelvin molecular samples can be conveniently obtained in our decelerator using a combined operation mode. These monochromatic beams are ideal starting points for precise studies of molecular collision, cold chemistry and high-resolution spectroscopy.

In this paper we present results on polarization-dependent laser-induced effects on titanium (Ti) thin films. We irradiated the titanium films, in ambient air, using a nanosecond Nd:YAG laser (532 nm, 9 ns pulse duration, 10 Hz). Using a series of pulses of fluence well below the ablation threshold, it was possible to form grating-like structures, whose grooves run parallel to the linear polarization of the incident beam. No grating-like structures were obtained when circularly polarizedlight was used. Our results revealed the remarkable formation of tiny (100 nm and even smaller diameter) craters, which self-arrange quasi-periodically along the ridges (never on the valleys) of the grating-like structure. Optical and scanning electron microscopy were used to study the laser-induced changes on the surface of the titanium films. Micro-Raman spectroscopy was used to analyze the irradiated areas on the titanium films. The Raman analysis demonstrated that the grooves in the grating-like structure, build up from the laser-induced oxidation of titanium. This is the first time, to the best of our knowledge, that periodic surface structures are reported to be induced below the ablation threshold regime, with the grooves made of crystalline metal oxide, in this case TiO{sub 2} in the well-known Rutile phase. The laser irradiated areas on the film acquired selective (upon recording polarization) holographic reflectance.

Tightly focused vectorial optical beams have found extensive applications in variety of technical fields like single-molecule detection, optical tweezers, and super-resolution optical microscopy. Such applications require an accurate measurement and manipulation of focal optical fields. We have developed a compact instrument (with dimensions of 35 × 35 × 30 cm3) to rapidly measure the intensity distribution in three dimensions of the focused fields of vectorial beams and any other incident beams. This instrument employs a fluorescent nanoparticle as a probe to scan the focal region to obtain a high spatial resolution of intensity distribution. It integrates a liquid-crystal spatial light modulator to allow for tailoring the point spread function of the optical system, making it a useful tool for multi-purpose and flexible research. The robust applicability of the instrument is verified by measuring the 3D intensity distributions of focal fields of various polarization and wavefront modulated incident beams focused by a high NA (=1.25) objective lens. The minimal data acquisition time achievable in the experiment is about 8 s for a scanning region of 3.2 × 3.2 μm2 (512 × 512 pixels). The measured results are in good agreement with those predicted by the vectorial diffraction theory.

A linear to radial and/or azimuthal polarization converter (LRAC) has been inserted into the beam delivery of a micromachining station equipped with a picosecond laser system. Percussion drilling and helical drilling in steel have been performed using radially as well as azimuthally polarized infrared radiation at 1030 nm. The presented machining results are discussed on the basis of numerical simulations of the polarization-dependent beam propagation inside the fabricated capillaries.

Electrical tuning of polarizationbeam splitting is demonstrated in the structure of symmetrical metal-cladding waveguide by introducing optically nonlinear material into both the coupling prism and the guiding layer. Due to the anisotropy of the coupling material, different excitation conditions for TE and TM modes are obtained, which results in polarization-dependent reflections and transmissions. And the splitting effect of the two orthogonally polarizedbeams can be manipulated through an electrical modulation of the guiding layer properties.

Nuclear spin polarization of an atomic /sup 23/Na-beam was produced by a combination of optical pumping with a dye laser and a sextupole magnet and alternatively, by optical pumping with two dye lasers. The maximum value measured for the vector polarization was P/sub 2/ = 0.86 +- 0.08, using beam foil spectroscopy. Further improvements of polarized ion sources based on this principle are discussed.

At the international linear collider large beampolarization of both the electron and positron beams will enhance the signature of physics due to interactions that are beyond the standard model. Here we review our recently obtained results on a general model-independent method of determining for an arbitary one-particle inclusive state the space-time structure of such new physics through the beampolarization dependence and angular distribution of the final state particle.

Compton scattering of twisted photons is investigated within a non-relativistic framework using first-order perturbation theory. We formulate the problem in the density matrix theory, which enables one to gain new insights into scattering processes of twisted particles by exploiting the symmetries of the system. In particular, we analyze how the angular distribution and polarization of the scattered photons are affected by the parameters of the initial beam such as the opening angle and the projection of orbital angular momentum. We present analytical and numerical results for the angular distribution and the polarization of Compton scattered photons for initially twisted light and compare them with the standard case of plane-wave light.

The vectorial beam propagation method has successfully been applied to a passive polarization converting waveguide structure. A complete polarization conversion has been simulated. The propagating fields are calculated and the power attenuation is evaluated. The influence of structural changes of the device on the polarization conversion is investigated.

Linearized field equations and solutions are derived for a perturbed sheet beam of light. The work is based on an exact solution of a collimated beam in the geometrical limit. The linearized field changes of the initially curved background metric can be put, with the help of the harmonic conditions, into a normal coordinate form. These six normal coordinates satisfy six linearized, inhomogeneous, field equations in three variables. Stationary solutions include divergent beams. Gravitational waves propagating opposite to the beam's flux are found to be confined to a region about the propagation axis of the beam, much as is experienced in wave guides. Radiative cases can be produced by large angle scattering of light and are discussed in terms of their effect on an ideal optical antenna. The effect is one that grows linearly with time. The growth time is prohibitively long for the most energetic systems that can be realistically considered in the foreseeable future.

When a coherent laser beam impinges on a random sample (e.g. a colloidal suspension), the scattered light exhibits characteristic speckles. If the temporal coherence of the light source is too short, then the speckles disappear, along with the possibility of performing homodyne or heterodyne scattering detection or photon correlation spectroscopy. Here we investigate the scattering of a so-called "skewed coherence beam", i.e., a short-coherence beam modified such that the field is coherent within slabs that are skewed with respect to the wave fronts. We show that such a beam generates speckles and can be used for heterodyne scattering detection, despite its short temporal coherence. When applied to quite turbid samples, the technique has the remarkable advantage of suppressing the multiple scattering contribution of the scattering signal. The phenomenon presented here represents a very effective method for measuring the coherence skewness of either a continuous wave or a pulsed beam. Another field of applicat...

The appearance of unconventional vacuum properties in intense fields has long been an active field of research. In this paper the vacuum polarization effect is investigated via a pump probe scheme of a probe light propagating in the vacuum excited by two counter-propagating laser beams. The modified light cone condition of the probe light is derived analytically for the situation that it passes through the electric/magnetic antinode plane of the pump field. The derivation does not follow the commonly adopted assumption of treating the pump field as a constant field. Differences from the conventional light cone conditions are identified. The implications of the result are discussed with a consideration of the vacuum birefringence measurement.

Solitary foraging ants have a navigational toolkit, which includes the use of both terrestrial and celestial visual cues, allowing individuals to successfully pilot between food sources and their nest. One such celestial cue is the polarization pattern in the overhead sky. Here, we explore the use of polarizedlight during outbound and inbound journeys and with different home vectors in the nocturnal bull ant, Myrmecia midas. We tested foragers on both portions of the foraging trip by rotating the overhead polarization pattern by ±45°. Both outbound and inbound foragers responded to the polarizedlight change, but the extent to which they responded to the rotation varied. Outbound ants, both close to and further from the nest, compensated for the change in the overhead e-vector by about half of the manipulation, suggesting that outbound ants choose a compromise heading between the celestial and terrestrial compass cues. However, ants returning home compensated for the change in the e-vector by about half of the manipulation when the remaining home vector was short (1-2 m) and by more than half of the manipulation when the remaining vector was long (more than 4 m). We report these findings and discuss why weighting on polarization cues change in different contexts.

Considering sum-frequency generation in an isotropic chiral nonlinear medium, we analyze the transfer of the spin angular momentum of fundamental elliptically polarized Gaussian lightbeams to the signal beam, which appears as the superposition of two Laguerre-Gaussian modes with both spin and orbital angular momentum. Only for the circular polarization of the fundamental radiation is its angular momentum fully transferred to the sum-frequency beam; otherwise, part of it can be transferred to the medium. Its value, as well as the ratio of spin and orbital contributions in the signal beam, depends on the fundamental frequency ratio and the polarization of the incident beams. Higher energy conversion efficiency in sum-frequency generation does not always correspond to higher angular momentum conversion efficiency.

A simplified method of generating a beam of light having a relatively high value of angular momentum (see figure) involves the use of a compact apparatus consisting mainly of a laser, a whispering- gallery-mode (WGM) resonator, and optical fibers. The method also can be used to generate a Bessel beam. ( Bessel beam denotes a member of a class of non-diffracting beams, so named because their amplitudes are proportional to Bessel functions of the radii from their central axes. High-order Bessel beams can have high values of angular momentum.) High-angular-momentum lightbeams are used in some applications in biology and nanotechnology, wherein they are known for their ability to apply torque to make microscopic objects rotate. High-angular-momentum lightbeams could also be used to increase bandwidths of fiber-optic communication systems. The present simplified method of generating a high-angular-momentum lightbeam was conceived as an alternative to prior such methods, which are complicated and require optical setups that include, variously, holograms, modulating Fabry-Perot cavities, or special microstructures. The present simplified method exploits a combination of the complex structure of the electromagnetic field inside a WGM resonator, total internal reflection in the WGM resonator, and the electromagnetic modes supported by an optical fiber. The optical fiber used to extract light from the WGM resonator is made of fused quartz. The output end of this fiber is polished flat and perpendicular to the fiber axis. The input end of this fiber is cut on a slant and placed very close to the WGM resonator at an appropriate position and orientation. To excite the resonant whispering- gallery modes, light is introduced into the WGM resonator via another optical fiber that is part of a pigtailed fiber-optic coupler. Light extracted from the WGM resonator is transformed into a high-angular- momentum beam inside the extraction optical fiber and this beam is emitted from the

Bessel beams are non-diffracting light structures, which maintain their spatial features after meters of propagation and are realized with simple optical elements such as axicon lenses, spatial filters, and lasers. In this paper, we demonstrate a method for generating non diffractive Bessel-like beams through a heavily scattering system, exploiting wavefronts shaped by a spatial light modulator. With the proposed method starting from amorphous speckle patterns, it is possible to produce at user defined positions configurable and non-diffracting light distributions which can improve depth-of-field in speckled illumination microscopy.

Collisions of light photons with relativistic electrons have previously been used to produce polarized ..gamma..-ray beams with modest (-10%) resolution but relatively low intensity. In contrast, the LEGS project (Laser + Electron Gamma Source) at Brookhaven will produce a very high flux (>2 x 10/sup 7/ s/sup -1/) of background-free polarized ..gamma.. rays whose energy will be determined to a high accuracy (..delta..E = 2.3 MeV). Initially, 300(420)-MeV ..gamma.. rays will be produced by backscattering uv light from the new 2.5(3.0)-GeV X-ray storage ring of the National Synchrotron Light Source (NSLS). The LEGS facility will operate as one of many passive users of the NSLS. In a later stage of the project, a Free Electron Laser is expectred to extend the ..gamma..-ray energy up to 700 MeV.

The wavelength-dependent optical torques provided by a circularly polarized (CP) plane wave driving Au nanorod (NR) and nanowire (NW) to rotate constantly were studied theoretically. Using the multiple multipole method, the resultant torque in terms of Maxwell's stress tensor was analyzed. Numerical results show that the optical torque spectrum is in accordance with the absorption spectrum of Au NR/NW. Under the same fluence, the maximum optical torque occurs at the longitudinal surface plasmon resonance (LSPR) of Au NR/NW, accompanied by a severe plasmonic heating. The rotation direction of the light-driven NR/NW depends on the handedness of CP light. In contrast, the optical torque exerted on Au NR/NW illuminated by a linearly polarizedlight is null at LSPR. Due to the plasmonic effect, the optical torque on Au NR/NW by CP light is two orders of magnitude larger than that on a dielectric NR/NW of the same size. The steady-state rotation of NR/NW in water, resulting from the balance of optical torque and viscous torque, was also discussed. Our finding shed some light on manipulating a CP light-driven Au NR/NW as a rotating nanomotor for a variety of applications in optofluidics and biophysics.

We propose a novel technique to directly transform a linearly polarized Gaussian beam into vector-vortex beams with various spatial patterns. Full high-quality control of amplitude and phase is implemented via a Digital Micro-mirror Device (DMD) binary holography for generating Laguerre-Gaussian, Bessel-Gaussian, and helical Mathieu–Gaussian modes, while a radial polarization converter (S-waveplate) is employed to effectively convert the optical vortices into cylindrically polarized vortex beams. Additionally, the generated vector-vortex beams maintain their polarization symmetry after arbitrary polarization manipulation. Due to the high frame rates of DMD, rapid switching among a series of vector modes carrying different orbital angular momenta paves the way for optical microscopy, trapping, and communication.

Full Text Available Investigations of the effects of optical transition radiation (OTR polarization components on beam profiles are presented. The transverse profiles are examined using the OTR perpendicular and parallel polarization components with respect to the dimension of interest. We observed ∼15% projected profile size reductions with the perpendicularly polarized components on a 65-μm beam image size case at 14 MeV, a 150-μm beam image size at 4.5 GeV, and a 1100-μm beam image size at 7 GeV. These effects are all several times larger than expected (and anomalous in this sense when compared to the standard OTR point-spread function calculations. We propose the time-averaged induced-current distribution which generates the OTR represents the actual beam size more faithfully with the perpendicular polarization component and recommend its routine use and subsequent deconvolution.

We report on the generation and control of quasi-Bessel beams having not only a uniform axial intensity but also a longitudinally varying polarization state. Based on the optimization routine of the spatial spectrum of the so-called Durnin ring, we generate quasi-Bessel beams possessing longitudinally variant axial intensity with linear or sinusoidal envelopes. By utilizing a Sagnac interferometer, we create and coaxially composite two orthogonally polarizedbeams with complementary axial intensities to form quasi-Bessel beams with uniform axial intensity but a longitudinally varying polarization state. Furthermore, we demonstrate the possibility and flexibility of manipulating the trajectory, speed, and period of polarization state transformation upon propagation. Our results may enable Bessel beams to be used in other applications including optical communications, material processing, and polarimetry.

@@ According to the vectorial structure of non-paraxial electromagnetic beams and the method of stationary phase,the analytical TE and TM terms of non-paraxial linearly polarized Gaussian beam are presented in the far field.The influence of linearly polarized angle on the relative energy flux distributions of the whole beam and its TE and TM terms is studied. The beam spot of the TE term is perpendicular to the direction of linearly polarized angle, while that of the TM term coincides with the direction of linearly polarized angle. The whole beam spot is elliptical, and the long axis is located at the direction of linearly polarized angle. The relative energy flux distribution of the TE term is relatively centralized in the direction perpendicular to the linearly polarized angle.While that of the TM term is relatively centralized in the direction of linearly polarized angle. To obtain the isolated TM and TE terms, a polarizer should be put at the long and the short axis of the whole beam. spot,respectively.

This work continues previous research about multiple scattering of polarizedlight propagation in turbid media, putting emphasis on the imaginary part of the scatterers' complex refractive index. The whole angle-dependent Müller matrix is evaluated by comparing results of a polarization sensitive radiative transfer solution to Maxwell theory. Turbid media of defined scatterer concentrations are modelled in three dimensions by sphere ensembles kept inside a cubic or spherical simulation volume. This study addresses the impact of absorption on polarization characteristics for selected media from low to high absorption. Besides that, effects caused by multiple and dependent scattering are shown for increasing volume concentration. In this context some unique properties associated with multiple scattering and absorption are pointed out. Further, scattering results in two dimensions are compared for examples of infinite parallel cylinders of high absorption and perpendicularly incident plane waves.

GRB afterglow polarization is discussed. We find an observable, up to 10%, polarization, if the magnetic field coherence length grows at about the speed of light after the field is generated at the shock front. Detection of a polarized afterglow would show that collisionless ultrarelativistic shocks can generate strong large scale magnetic fields and confirm the synchrotron afterglow model. Non-detection, at a 1% level, would imply that either the synchrotron emission model is incorrect, or that strong magnetic fields, after they are generated in the shock, somehow manage to stay un-dissipated at ``microscopic'', skin depth, scales. Analytic lightcurves of synchrotron emission from an ultrarelativistic self-similar blast wave are obtained for an arbitrary electron distribution function, taking into account the effects of synchrotron cooling. The peak synchrotron flux and the flux at frequencies much smaller than the peak frequency are insensitive to the details of the electron distribution function; hence the...

The sky lightpolarization navigator has many advantages, such as low cost, no decrease in accuracy with continuous operation, etc. However, current celestial polarization measurement methods often suffer from low performance when the sky is covered by clouds, which reduce the accuracy of navigation. In this paper we introduce a new method and structure based on a handheld light field camera and a radial polarizer, composed of an S-wave plate and a linear polarizer, to detect the sky lightpolarization pattern across a wide field of view in a single snapshot. Each micro-subimage has a special intensity distribution. After extracting the texture feature of these subimages, stable distribution information of the angle of polarization under a cloudy sky can be obtained. Our experimental results match well with the predicted properties of the theory. Because the polarization pattern is obtained through image processing, rather than traditional methods based on mathematical computation, this method is less sensitive to errors of pixel gray value and thus has better anti-interference performance.

The use of spirally polarizedbeams (SPBs) in polarimetric measurements of homogeneous and deterministic samples is proposed. Since across any transverse plane such beams present all possible linearly polarized states at once, the complete Mueller matrix of deterministic samples can be recovered with a reduced number of measurements and small errors. Furthermore, SPBs present the same polarization pattern across any transverse plane during propagation, and the same happens for the field propagated after the sample, so that both the sample plane and the plane where the polarization of the field is measured can be chosen at will. Experimental results are presented for the particular case of an azimuthally polarizedbeam and samples consisting of rotated retardation plates and linear polarizers.

As the world's first high energy polarized proton collider, RHIC has made significant progresses in measuring the proton spin structure in the past decade. In order to have better understanding of the contribution of up quarks and down quarks to the proton spin structure, collisions of high energy polarized neutron beams are required. Polarized He-3 beams offer an effectiveway to provide polarized neutron beams. In this paper, we present studies of accelerating polarized He-3 in RHIC with the current dual snake configuration. Possibilities of adding two more pairs of snakes for accelerating polarized He-3 were explored. Results of six snake configuration in RHIC are also reported in the paper.

Polarized {sup 3}He has shown its unique characteristics in many areas of polarized neutron scattering, its ability to polarize neutrons at short wavelengths, accept wide-angle and divergent beams and low backgrounds enable new classes of experiments. While polarized {sup 3}He is not a steady state solution as commonly applied, the benefits have been shown to offset the drawbacks of polarizing and refreshing the polarization in the neutron spin filter cells. As an extension of this work, in-situ polarization using the spin-exchange optical pumping (SEOP) method was explored as a means to construct a system which could be used to polarize {sup 3}He in the state used for an effective neutron spin filter to constant polarization while on the neutron beam. An in-situ SEOP polarizer was constructed. This device utilized many devices and principles developed for neutron spin filters which are polarized off the beam line using either SEOP or metastability exchange optical pumping (MEOP) under the same research program. As a collimation of this work effects of extremely high neutron capture flux density >1x10{sup 10}cm{sup -2}s{sup -1} incident on the in-situ polarizer were explored.

A T-shaped polarizationbeam splitter based on two-dimensional photonic crystal is proposed, which is composed of three waveguides: one input and two output. Unpolarized beams incident from the input port will be separated into two different polarization modes and outputted individually by two different coupling structures. Simulation results can be obtained by the finite-difference time-domain (FDTD) method. In the normalized frequency range of 0.3456 extinction ratio is all 30dB for both modes. The polarizationbeam splitter attains the requirement we expected by analyzing simulation results.

Following the suggestion by Jura and Jacoby (1976), linearly polarized blue continuum starlight scattered by the dust shell around the M2 Iab star Alpha Orionis (Betelgeuse) has been discovered. The polarization has been traced in the NE, NW, SE, and SW directions and has positive (tangential) orientation. Some asymmetry of the optical depth in the shell exists 15 and 30 arcsec from the star. In the NE direction the polarization was measured as far as 90 arcsec (17,000 AU) from the star. The dependence of the average intensity of the scattered light from the nebula on angular distance from the star is more consistent with an inverse-square density law than with inverse 1.5 or inverse-cube laws. Assuming that the density is proportional to the inverse square of distance from the star, the scattering optical depth in blue light along a radius of 0.03 arcsec is no more than 0.15 + or - 0.05. Future observations of the wavelength dependence of polarization will allow a determination of grain size.

Polarizedlight (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but in most other vertebrate classes, including birds, the behavioural and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system. PMID:21282180

Polarizedlight (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but in most other vertebrate classes, including birds, the behavioural and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system.

Adult tabanid flies (horseflies and deerflies) are terrestrial and lay their eggs onto marsh plants near bodies of fresh water because the larvae develop in water or mud. To know how tabanids locate their host animals, terrestrial rendezvous sites and egg-laying places would be very useful for control measures against them, because the hematophagous females are primary/secondary vectors of some severe animal/human diseases/parasites. Thus, in choice experiments performed in the field we studied the behavior of tabanids governed by linearly polarizedlight. We present here evidence for positive polarotaxis, i.e., attraction to horizontally polarizedlight stimulating the ventral eye region, in both males and females of 27 tabanid species. The novelty of our findings is that positive polarotaxis has been described earlier only in connection with the water detection of some aquatic insects ovipositing directly into water. A further particularity of our discovery is that in the order Diptera and among blood-sucking insects the studied tabanids are the first known species possessing ventral polarization vision and definite polarization-sensitive behavior with known functions. The polarotaxis in tabanid flies makes it possible to develop new optically luring traps being more efficient than the existing ones based on the attraction of tabanids by the intensity and/or color of reflected light.

Kapitza tandem structures, consisting of thin alternating layers with opposite signs of the dielectric permittivity, have been recently predicted to afford diffraction arrest of focused microwave radiation [Phys. Rev. Lett. 110, 143901 (2013)]. Here we study the applicability of the Kapitza effect to control the propagation of structured subwavelength lightbeams. We show that a sufficiently deep modulation of the dielectric permittivity allows a nearly complete diffraction cancellation of multiple-peak subwavelength beams, and we study how the degree of diffraction cancellation decreases as the spatial spectrum of the input beam broadens. We also find that subwavelength lightbeams can be steered by varying the depth of the permittivity modulation. In particular, a sufficiently large permittivity modulation is shown to cause otherwise titled inputs to propagate always along the direction of modulation.

(abridged) We review recent studies of chirality using circularly polarizedlight, along with the birth and evolution of life and planetary systems. Terrestrial life consists almost exclusively of one enantiomer, left-handed amino acids. This characteristic feature is called homochirality, whose origin is still unknown. The route to homogeneity of chirality would be connected with the origin and development of life on early Earth along with evolution of the solar system. Detections of enantio...

The spectral and angle-dependent optical properties of two scarab beetle species belonging to the genus Chrysina are presented. The species display broadband reflectivity and selectively reflect left-circularly polarizedlight. We use electron microscopy to detail the left-handed, twisted lamellar structure present in these biological systems and imaging scatterometry to characterize their bidirectional reflectance distribution function. We show that the broadband nature of the beetles' reflectance originates due to the range of pitch dimensions found in the structure.

Arbitrary vector beams (VBs) are realized by the designed polarization converters and corresponding vector-photoaligned q-plates. The polarization converter is a specific twisted nematic cell with one substrate homogeneously aligned and the other space-variantly aligned. By combining a polarization-sensitive alignment agent with a dynamic micro-lithography system, various categories of liquid crystal polarization converters are demonstrated. Besides, traditional radially/azimuthally polarizedlight, high-order and multi-ringed VBs, and a VB array with different orders are generated. The obtained converters are further utilized as polarization masks to implement vector-photoaligning. The technique facilitates both the volume duplication of these converters and the generation of another promising optical element, the q-plate, which is suitable for the generation of VBs for coherent lasers. The combination of proposed polarization converters and correspondingly fabricated q-plates would drastically enhance the capability of polarization control and may bring more possibilities for the design of photonic devices.

The Next Generation Light Source will deliver high (MHz) repetition rate electron beams to an array of free electron lasers. Because of the significant average current in such a facility, effective beam collimation is extremely important to minimize radiation damage to undulators, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the early conceptual design of a collimation system, as well as initial results of simulations to test its effectiveness.

The need of didactic material is increasing in medical science nowadays. The lack of anatomical specimens, and the toxicity of conservators, have originated an intense search for alternative ways of demonstrating the human anatomy. As a solution for this difficulty, three-dimensional (3-D) images may be used, facilitating the learning process. This study aims at comparing and describing two techniques of reproduction of bi-dimensional images into three dimensions, which is called stereoscopy. The methods evaluated are filter of colors (anaglyphic) and polarizedlight. Techniques were analyzed for clearness and 3-D effect. Fourteen images were evaluated by 5 people, with scores ranging from 0 to 4. Total mean scores of polarizedlight was superior compared to the anaglyphic technique. Both methods use the codification of the image, which means separation and exclusivity with each eye seeing its corresponding image. After several photographic essays and gradual adaptation to a better technique, based on optical physics, photography and neuroanatomical knowledge, we concluded that both techniques are suitable means for production of 3-D images. The best technique, however, considering the final quality of image was polarizedlight, which did not alter the natural color of the specimen, conserving clearness of images with lower cost.

Radially polarized laser beam amplification up to the 772 mJ using flash-lamp-pumped Nd:YAG amplifiers was demonstrated. In the experiments, a nanosecond radially polarized seed beam was converted from a conventional Q-switched Nd:YAG laser output with a polarization converter and then amplified with two Nd:YAG amplifier stages. A maximum amplification output energy up to 772 mJ was achieved at 10 Hz with a 10-ns pulse, corresponding to an amplification factor of 323%. Excellent conservation of polarization was also obtained during the amplification.

We explore the discovery and analysis potentials of the HERA collider, with and without polarizedbeams, in search for electron-quark contact interactions in the neutral current channel. We find that the sensitivity to contact interactions when both beams are polarized is similar to the unpolarized case, and is better than in the case where one has only lepton polarization. We emphasize that the measurement of spin asymmetries in such a polarized context could give some crucial informations on the chiral structure of these postulated new interactions. The experimental conditions are carefully taken into account.

The use of resonant depolarization has been suggested for precise beam energy measurements (better than 100 keV) in the e$^+$e$^−$ Future Circular Collider (FCC-e$^+$e$^−$) for $Z$ and $WW$ physics at 45 and 80 GeV beam energy respectively. Longitudinal beampolarization would benefit the $Z$ peak physics program; however it is not essential and therefore it will be not investigated here. In this paper the possibility of self-polarized leptons is considered. Preliminary results of simulations in presence of quadrupole misalignments and beam position monitors (BPMs) errors for a simplified FCC-e$^+$e$^−$ ring are presented.

We report, in theory and experiment, on a novel class of controlled light capsules with nearly perfect darkness, directly employing intrinsic properties of modified Bessel-Gauss beams. These beams are able to naturally create three-dimensional bottle-shaped region during propagation as long as the parameters are properly chosen. Remarkably, the optical bottle can be controlled to demonstrate various geometries through tuning the beam parameters, thereby leading to an adjustable light capsule. We provide a detailed insight into the theoretical origin and characteristics of the light capsule derived from modified Bessel-Gauss beams. Moreover, a binary digital micromirror device (DMD) based scheme is first employed to shape the bottle beams by precise amplitude and phase manipulation. Further, we demonstrate their ability for optical trapping of core-shell magnetic microparticles, which play a particular role in biomedical research, with holographic optical tweezers. Therefore, our observations provide a new route for generating and controlling bottle beams and will widen the potentials for micromanipulation of absorbing particles, aerosols or even individual atoms.

In this work we have studied the distribution of a circularly polarizedbeam carrying the optical vortex with fractional topological charge equal to ½ in a uniaxial crystal. We have found that by increasing the angle of inclination of the beam relative to the optical axis of the crystal to α = 1.75 °, mixed dislocation movement observed wave front interference pattern to beam periphery. Experimental research has shown that when the angle α = 2 ° in the central region of the beam, we are seeing the emergence of "fork", optical vortex with a topological charge of the order of 1. The results show depolarization of the beam and the transition to the spin angular momentum of the orbital angular momentum. The intensity of the RCP and LCP component in the beam carrying the optical vortex with fractional topological charge oscillate. The total intensity of the beam as the sum of two orthogonally polarized components does not change.

The recent results by the PVLAS group on possible changes of polarization of laser light in a transverse magnetic field are beyond the QED expectations by many orders of magnitude. If confirmed, they may indicate new physics associated with ultra-light particles. I describe here how the polarization of light is modified in an external magnetic field by interactions with a spin-zero particle of no definite parity. While the PVLAS-type experiments cannot tell such a particle from one with definite parity, the parity property could be studied in photon regeneration experiments if the polarization of the regenerated photons could be measured. This talk was based on my recent work.

The Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab is designed to provide high polarization of both colliding beams. One of the unique features of JLab's MEIC is figure-8 shape of its rings. It allows preservation and control of polarization of all ion species including small-anomalous-magnetic-moment deuterons during their acceleration and storage. The figure-8 design conceptually expands the capability of obtaining polarized high-energy beams in comparison to conventional designs because of its property of having no preferred periodic spin direction. This allows one to control effectively the beampolarization by means of magnetic insertions with small field integrals. We present a complete scheme for preserving the ion polarization during all stages of acceleration and its control in the collider's experimental straights.

In this paper we analyze the polarization of the X-ray radiation coming from laser--electron X-ray generator (LEXG). We obtain general relations connecting the polarization state of outgoing X-ray radiation to the polarization state of laser beam as well as to the parameters of electron beam. We demonstrate that finite electron beam emittance causes a partial depolarization of initially fully polarized X-ray radiation even when the laser beam is fully polarized. We demonstrate with a number of numerical experiments that finite electron beam emittance can in some cases fundamentally alter the polarization state of X-ray radiation as compared to the polarization state of X-ray radiation scattered by electron beam with a zero emittance. Possible applications of polarized LEXG's radiation are discussed.

In this work, we investigate the topological phase transitions in graphene under the modulation of circularly polarizedlight, by analyzing the changes of edge states and its topological structures. A full phase diagram, with several different topological phases, is presented in the parameter space spanned by the driving frequency and light strength. We find that the high-Chern number behavior is very common in the driven system. While the one-photon resonance can create the chiral edge states in the π-gap, the two-photon resonance will induce the counter-propagating edge modes in the zero-energy gap. When the driving light strength is strong, the number and even the chirality of the edge states may change in the π-gap. The robustness of the edge states to disorder potential is also examined. We close by discussing the feasibility of experimental proposals.

We report a new imaging technique to study the morphology of living epithelial cells in vivo. The method is based on light scattering spectroscopy with polarizedlight (PLSS) and makes it possible to distinguish between single backscattering from epithelial cell nuclei and multiply scattered light. The spectrum of the single backscattering component is further analyzed to provide quantitative histological information about the epithelial cells such as the size distribution, refractive index, and chromatin content of the cell nuclei. The measurement of cell nuclear morphology is crucial for detection and diagnosis of cancerous and precancerous conditions in many human tissues. The method was successfully applied to image precancerous regions of several tissues. Clinical studies in five organs (esophagus, colon, bladder, oral cavity, and uterine cervix) showed the generality and efficacy of the technique.

By introducing an imaginary space transform curvature ρx, a complex space called Riemannian space is constructed, in which the light propagating in free space has the trajectory of straight line while propagating. Moreover, this curvature couples with that of the wave front of the paraxial beam ρw, and therefore a complex curvatureρe is constructed, which can be employed to investigate the behavior of the light transmission and to generalize the ABCD law.

Full Text Available A metasurface comprising an array of silver nanorods supported by a thin film of the phase change material vanadium dioxide is used to rotate the primary polarization axis of visible light at a pre-determined wavelength. The dimensions of the rods were selected such that, across the two phases of vanadium dioxide, the two lateral localized plasmon resonances (in the plane of the metasurface occur at the same wavelength. Illumination with linearly polarizedlight at 45° to the principal axes of the rod metasurface enables excitation of both of these resonances. Modulating the phase of the underlying substrate, we show that it is possible to reversibly switch which axis of the metasurface is resonant at the operating wavelength. Analysis of the resulting Stokes parameters indicates that the orientation of the principal linear polarization axis of the reflected signal is rotated by 90° around these wavelengths. Dynamic metasurfaces such as these have the potential to form the basis of an ultra-compact, low-energy multiplexer or router for an optical signal.

To compensate for the gain saturation effect in the high-energy laser amplifier, a modified polarizationbeam combination (PBC) method is introduced to reshape temporal waveform of the injected laser pulse to obtain a controlled high-energy laser pulse shape after amplification. One linearly polarizedbeam is divided into two orthogonal polarizedbeams, which spatially recombine together collinearly after propagating different optical paths with relative time delay in PBC structure. The obtained beam with polarization direction being rotated by the following half wave plate is divided and combined again to reform a new beam in another modified polarizationbeam structure. The reformed beam is injected into three cascaded laser amplifiers. The amplified pulse shape can be controlled by the incident pulse shape and amplifier gain, which is agreeable to the simulation by the Frank-Nodvik equations. Based on the simple method, the various temporal waveform of output pulse with tunable 7 to 20 ns pulse duration can be obtained without interferometric fringes.

The research developed in the framework of this PhD thesis is a theoretical, numerical and experimental study of lightbeam shaping (spatial filtering, beam collimation and focusing) in the visible frequency range using photonic crystal structures. Photonic crystals (PhCs) are materials with periodic, spatially modulated refractive index on the wavelength scale. They are primarily known for their chromatic dispersion properties. However, they can also modify the spatial dispersion, which allo...

Arrangements consisting of at least three beam splitting surfaces are described that give rise to at least four different beams, of which at least two have polarization-independent spectral intensities. They can act over a wide spectral region and can be designed to be either achromatic or color selective. The performance of an experimentally produced device is described.

We experimentally demonstrate the generation of radially polarized Bessel-Gaussian beams from a c-cut Nd:YVO₄ laser with a hemispherical cavity configuration by proper mode control. The output beam has an annular-shaped intensity distribution with radial polarization. When the beam is focused, the intensity pattern changes to a multi-ring, which is a typical characteristic of the lowest transverse mode of vector Bessel-Gaussian beam. Higher-order modes of vector Bessel-Gaussian beam are also observed from the same cavity by slightly changing the cavity alignment. The experimental results show a good agreement with the simulation results for both focal and far fields. The present method is a simple and direct way for generating vector Bessel-Gaussian beams.

Multi-quantum well (MQW) structures and light emitting diodes (LEDs) were grown on semipolar (2021) and polar (0001) GaN substrates by plasma-assisted molecular beam epitaxy. The In incorporation efficiency was found to be significantly lower for the semipolar plane as compared to the polar one. The semipolar MQWs exhibit a smooth surface morphology, abrupt interfaces, and a high photoluminescence intensity. The electroluminescence of semipolar (2021) and polar (0001) LEDs fabricated in the same growth run peaks at 387 and 462 nm, respectively. Semipolar LEDs with additional (Al,Ga)N cladding layers exhibit a higher optical output power but simultaneously a higher turn-on voltage.

SLAC E-158 is an experiment designed to make the first measurement of parity violation in Moeller scattering. E-158 will measure the right-left cross-section asymmetry, A{sub LR}{sup Moeller}, in the elastic scattering of a 45-GeV polarized electron beam from unpolarized electrons in a liquid hydrogen target. E-158 plans to measure the expected Standard Model asymmetry of {approx}10{sup -7} to an accuracy of better than 10{sup -8}. To make this measurement, the photoemission-based polarized electron source requires an intense circularly polarized laser beam and the ability to quickly switch between right- and left-helicity polarization states with minimal right-left helicity-correlated asymmetries in the resulting beam parameters (intensity, position, angle, spot size, and energy), {sup beam}A{sub LR}'s. This laser beam is produced by a unique SLAC-designed flashlamp-pumped Ti:Sapphire laser and is directed through a carefully designed set of polarization optics. We analyze the transport of nearly circularly polarizedlight through the optical system and identify several mechanisms that generate {sup beam}A{sub LR}'s. We show that the dominant effects depend linearly on particular polarization phase shifts in the optical system. We present the laser system design and a discussion of the suppression and control of {sup beam}A{sub LR}'s. We also present results on beam performance from engineering and physics runs for E-158.

We have proposed a method to generate almost linearly polarized resonant transition radiation X rays by using a rectangular slit placed on an electron beam axis. Our calculation predicted that the linearity is 93.5% for the resonant transition radiation X-ray beam extracted through a slit of 0.5 mrad long and 0.2 mrad wide in case of 1-GeV electron beam irradiating a 7.5-{mu}m thick Kapton foil stack. (author)

Circularly polarizedlight is utilized in various optical techniques and devices. However, using conventional optical systems to generate, analyse and detect circularly polarizedlight involves multiple optical elements, making it challenging to realize miniature and integrated devices. While a number of ultracompact optical elements for manipulating circularly polarizedlight have recently been demonstrated, the development of an efficient and highly selective circularly polarizedlight photodetector remains challenging. Here we report on an ultracompact circularly polarizedlight detector that combines large engineered chirality, realized using chiral plasmonic metamaterials, with hot electron injection. We demonstrate the detector's ability to distinguish between left and right hand circularly polarizedlight without the use of additional optical elements. Implementation of this photodetector could lead to enhanced security in fibre and free-space communication, as well as emission, imaging and sensing applications for circularly polarizedlight using a highly integrated photonic platform.

Circularly polarizedlight is utilized in various optical techniques and devices. However, using conventional optical systems to generate, analyse and detect circularly polarizedlight involves multiple optical elements, making it challenging to realize miniature and integrated devices. While a number of ultracompact optical elements for manipulating circularly polarizedlight have recently been demonstrated, the development of an efficient and highly selective circularly polarizedlight photodetector remains challenging. Here we report on an ultracompact circularly polarizedlight detector that combines large engineered chirality, realized using chiral plasmonic metamaterials, with hot electron injection. We demonstrate the detector's ability to distinguish between left and right hand circularly polarizedlight without the use of additional optical elements. Implementation of this photodetector could lead to enhanced security in fibre and free-space communication, as well as emission, imaging and sensing applications for circularly polarizedlight using a highly integrated photonic platform.

The present study first examined whether ruin lizards, Podarcis sicula, are able to orientate using plane-polarizedlight produced by an LCD screen. Ruin lizards were trained and tested indoors, inside a hexagonal Morris water maze positioned under an LCD screen producing white polarizedlight with a single E-vector, which provided an axial cue. White polarizedlight did not include wavelengths in the UV. Lizards orientated correctly either when tested with E-vector parallel to the training axis or after 90 deg rotation of the E-vector direction, thus validating the apparatus. Further experiments examined whether there is a preferential region of the light spectrum to perceive the E-vector direction of polarizedlight. For this purpose, lizards reaching learning criteria under white polarizedlight were subdivided into four experimental groups. Each group was tested for orientation under a different spectrum of plane-polarizedlight (red, green, cyan and blue) with equalized photon flux density. Lizards tested under blue polarizedlight orientated correctly, whereas lizards tested under red polarizedlight were completely disoriented. Green polarizedlight was barely discernible by lizards, and thus insufficient for a correct functioning of their compass. When exposed to cyan polarizedlight, lizard orientation performances were optimal, indistinguishable from lizards detecting blue polarizedlight. Overall, the present results demonstrate that perception of linear polarization in the blue is necessary - and sufficient - for a proper functioning of the sky polarization compass of ruin lizards. This may be adaptively important, as detection of polarizedlight in the blue improves functioning of the polarization compass under cloudy skies, i.e. when the alternative celestial compass based on detection of the sun disk is rendered useless because the sun is obscured by clouds.

We study radiative corrections to chargino production at linear colliders with polarized electron beams. We calculate the one-loop corrected cross sections for polarized electon beams due to three families of quarks and squarks, working in the {ovr MS} scheme, extending our previous calculation of the unpolarized cross section with one-loop corrections due to the third family of quarks and squarks. In some cases we find rather large corrections to the tree-level cross sections. For example, for the case of right-handed polarized electrons and large tan{beta} the corrections can be of order 30%, allowing sensitivity to the squark mass parameters.

@@ The propagation of polychromatic electromagnetic Gaussian Schell-model (EGSM) beams in free space is investigated. It is shown that the spectral degree of polarization, spectral degree of coherence, and normalized spectrum change generally on propagation. The conditions of keeping the spectral invariance and keeping polarization invariance for the polychromatic EGSM beams are derived respectively. The results indicate that the constraints on the parameters of EGSM source to keep polarization invariance on propagation are more rigorous than those to keep invariance of the normalized spectrum.

The Compton scattering of a circularly polarized laser beam condensed by an optical resonator can be used for multipass measurement of beam profile, position, and polarization in CEBAF`s 250-m-long linac straight sections. The position and profile of the beam will be measured with an accuracy of {approximately}10 {mu}m in about 200 seconds and beampolarization with 10% accuracy in 100 seconds when the lowest beam energy is 500 MeV and the beam current is 100 {mu}A. For higher energies the times for measurement are much less. The photon target is within an optical resonator having a quality factor of 50. The Nd:Yag 5 W CW laser photon beam at wavelength {lambda} = 0.532 nm will have a waist {omega}{sub o} {approximately}30 {mu}m and a Rayleigh range of about 10 mm. Scanning the electron beams in the linac sections by this photon beam at a crossing angle of 0.1 rad will send to a proportional detector installed after the spreader magnet scattered photons with energies sharply correlated with the energy of the electrons.

We propose an approach to actively tune the scattering pattern of a Mie-type spherical antenna. The scheme is based on separate control over the induced electric dipole and induced magnetic dipole using two coherent focused beams of radial polarization and azimuthal polarization. By carefully tuning the amplitude and phase relation of the two beams, a broadband unidirectional scattering can be achieved, even at the wavelength where the antenna scatters most efficiently. By moving the focus of one beam, a drastic switch of the unidirectional scattering can be observed. Such scheme enables the design of ultra-compact optical switches and directional couplers based on nanoantennas.

We propose a new approach for generating a multiple focal spot segment of subwavelength size, by tight focusing of a phase modulated radially polarized Laguerre Bessel Gaussian beam. The focusing properties are investigated theoretically by vector diffraction theory. We observe that the focal segment with multiple focal structures is separated with different axial distances and a super long dark channel can be generated by properly tuning the phase of the incident radially polarized Laguerre Bessel Gaussian beam. We presume that such multiple focal patterns and high intense beam may find applications in atom optics, optical manipulations and multiple optical trapping.

We report the room-temperature electroluminescence (EL) with nearly pure circular polarization (CP) from GaAs-based spin-polarizedlight-emitting diodes (spin-LEDs). External magnetic fields are not used during device operation. There are two small schemes in the tested spin-LEDs: firstly, the stripe-laser-like structure that helps intensifying the EL light at the cleaved side walls below the spin injector Fe slab, and secondly, the crystalline AlOx spin tunnel barrier that ensures electrically stable device operation. The purity of CP is depressively low in the low current density (J) region, whereas it increases steeply and reaches close to the pure CP when J = 100 A/cm2. There, either right- or left-handed CP component is significantly suppressed depending on the direction of magnetization of the spin injector. Spin-polarized-current induced birefringence and optical spin-axis conversion are suggested to account for the observed experimental results.

Sum-frequency generation (SFG) is investigated using the two-coupled-oscillator molecular model. The influence of the polarization states and angles of two incident beams on reflected and transmitted sum-frequency lights is discussed by considering the circular birefringence in a chiral medium. The different response of media with two kinds of enantiomers to polarization states of incident beams is also discussed. Furthermore, the relations between the SFG spectrum and the polarization states are studied. The theoretical result is consistent with a known experimental fact.

We present a detailed study of two novel methods for shaping the light optical wavefront by employing a transmissive spatial light modulator (SLM). Conventionally, optical Airy beams are created by employing SLMs in the so-called all phase mode. In this mode, a cubic phase distribution is transferred onto an SLM and its Fourier transform generates an Airy beam. The Fourier transform is obtained at the back focal plane of the lens, by employing a physical lens behind the SLM. We show that such an approach fails when a transmissive SLM is used; we present an alternative method for creating Airy beams. In our method, a numerically simulated lens phase distribution is transferred directly onto the SLM, together with the cubic phase distribution. An Airy beam is obtained by the Fourier transform of the cubic phase distribution and is generated behind the SLM, at the focal plane of the numerical lens. We study the deflection properties of the so formed Airy beam and derive the formula for deflection of the intensit...

We theoretically investigate a switchable spin Hall effect of light (SHEL) in reflection for three specific dispersion relations at an air-anisotropic metamaterial interface.The displacements of horizontal and vertical polarization components vary with the incident angle at different dispersion relations.The transverse displacements can be obtained with the relevant metamaterial whose refractive index can be arbitrarily tailed.The results of the SHEL in the metamaterial provide a new way for manipulating the transverse displacements of a specific polarization component.

We present a digital holography microscopy technique based on parallel-quadrature phase-shifting method. Two π/2 phase-shifted holograms are recorded simultaneously using polarization phase-shifting principle, slightly off-axis recording geometry, and two identical CCD sensors. The parallel phase-shifting is realized by combining circularly polarized object beam with a 45° degree polarized reference beam through a polarizingbeam splitter. DC term is eliminated by subtracting the two holograms from each other and the object information is reconstructed after selecting the frequency spectrum of the real image. Both amplitude and phase object reconstruction results are presented. Simultaneous recording eliminates phase errors caused by mechanical vibrations and air turbulences. The slightly off-axis recording geometry with phase-shifting allows a much larger dimension of the spatial filter for reconstruction of the object information. This leads to better reconstruction capability than traditional off-axis holography.

A recent experiment in the IUCF cooler ring studied the spin flip of a stored vertically polarized 139 MeV proton beam. This spin flip was accomplished by using an RF solenoid to induce an artificial depolarizing resonance in the ring, and then varying the solenoid's frequency through this resonance value to induce spin flip. We found a polarization loss after multiple spin flips of about 0.00±0.05% per flip and also losses for very long flip times. This device will be useful for reducing systematic errors in polarizedbeam-internal target scattering asymmetry experiments by enabling experimenters to perform frequent beampolarization reversals in the course of the experiment.

Full Text Available The problems of spin-polarized free-electron beam interaction with electromagnetic wave at electron-spin resonance conditions in a magnetic field and of superradiant spin-flip radiative emission are analyzed in the framework of a comprehensive classical model. The spontaneous emission of spin-flip radiation from electron beams is very weak. We show that the detectivity of electron spin resonant spin-flip and combined spin-flip/cyclotron-resonance-emission radiation can be substantially enhanced by operating with ultrashort spin-polarized electron beam bunches under conditions of superradiant (coherent emission. The proposed radiative spin-state modulation and the spin-flip radiative emission schemes can be used for control and noninvasive diagnostics of polarized electron/positron beams. Such schemes are of relevance in important scattering experiments off nucleons in nuclear physics and off magnetic targets in condensed matter physics.

In order to control and analyze lightpolarization, we design a magnetic resonator and study its transmission properties by the 4 Multiplication-Sign 4 transfer matrix method. Through the magnetic resonator an incidence of elliptically polarizedlight results in two resonance wavelengths. At the two resonance wavelengths, the elliptically polarizedlight is orthogonally decomposed into left-handed circular polarization and right-handed circular polarization. One of the two circular polarizations is transmitted and the other is reflected. - Highlights: Black-Right-Pointing-Pointer Magnetic film is sandwiched between two identical metal films. Black-Right-Pointing-Pointer There are two resonant wavelengths for the incident elliptically polarizedlight. Black-Right-Pointing-Pointer The incident light is orthogonally decomposed into two circular polarizations at the two wavelengths.

Multifragmentation studies with GeV light-ion beams indicate that for the most violent collisions, complex fragments are emitted during expansion of the hot source, followed by near simultaneous breakup of the system near rho/rho sub o approx ((1)/(3)). The results are compared with hybrid INC/EES and INC/SMM models. Preliminary data for the 8 GeV/c pi sup - and p-bar reactions on sup 1 sup 9 sup 7 Au show enhanced deposition energy for the antiproton beam.

Using the coherence theory of non-stationary fields and the characterization of stochastic electromagnetic pulsed beams, the analytical expression for the spectral degree of polarization of stochastic electromagnetic Gaussian Schell-model pulsed (GSMP) beams in turbulent atmosphere is derived and is used to study the polarization properties of stochastic electromagnetic GSMP beams propagating through turbulent atmosphere. The results of numerical calculation are given to illustrate the dependence of spectral degree of polarization on the pulse frequency, refraction index structure constant and spatial correlation length. It is shown that, compared with free-space case, in turbulent atmosphere propagation there are two positions at which the on-axis spectral degree of polarization P is equal to zero. The position change depends on the pulse frequency, refraction index structure constant and spatial correlation length.%@@ Using the coherence theory of non-stationary fields and the characterization of stochastic electromagnetic pulsed beams, the analytical expression for the spectral degree of polarization of stochastic electromagnetic Gaussian Schell-model pulsed (GSMP) beams in turbulent atmosphere is derived and is used to study the polarization properties of stochastic electromagnetic GSMP beams propagating through turbulent atmosphere.The results of numerical calculation are given to illustrate the dependence of spectral degree of polarization on the pulse frequency, refraction index structure constant and spatial correlation length.It is shown that, compared with free-space case, in turbulent atmosphere propagation there are two positions at which the on-axis spectral degree of polarization P is equal to zero.The position change depends on the pulse frequency, refraction index structure constant and spatial correlation length.

We consider the possibility of new physics giving rise to effective interactions of the form e+e- Hf f bar , where f represents a charged lepton ℓ or a (light) quark q, and H the recently discovered Higgs boson. Such vertices would give contributions beyond the standard model to the Higgs production processes e+e- → Hℓ+ℓ- and e+e- → Hq q bar at a future e+e- collider. We write the most general form for these vertices allowed by Lorentz symmetry. Assuming that such interactions contribute in addition to the standard model production processes, where the final-state fermion pair comes from the decay of the Z boson, we obtain the differential cross section for the processes e+e- → Hℓ+ℓ- and e+e- → Hq q bar to linear order in the effective interactions. We propose several observables with differing CP and T properties which, if measured, can be used to constrain the couplings occurring in interaction vertices. We derive possible limits on these couplings that may be obtained at a collider with centre-of-mass energy of 500 GeV and an integrated luminosity of 500 fb-1. We also carry out the analysis assuming that both the electron and positron beams can be longitudinally polarized, and find that the sensitivity to the couplings can be improved by a factor of 2-4 by a specific choice of the signs of the polarizations of both the electron and positron beams for the same integrated luminosity.

Full Text Available We consider the possibility of new physics giving rise to effective interactions of the form e+e−Hff¯, where f represents a charged lepton ℓ or a (light quark q, and H the recently discovered Higgs boson. Such vertices would give contributions beyond the standard model to the Higgs production processes e+e−→Hℓ+ℓ− and e+e−→Hqq¯ at a future e+e− collider. We write the most general form for these vertices allowed by Lorentz symmetry. Assuming that such interactions contribute in addition to the standard model production processes, where the final-state fermion pair comes from the decay of the Z boson, we obtain the differential cross section for the processes e+e−→Hℓ+ℓ− and e+e−→Hqq¯ to linear order in the effective interactions. We propose several observables with differing CP and T properties which, if measured, can be used to constrain the couplings occurring in interaction vertices. We derive possible limits on these couplings that may be obtained at a collider with centre-of-mass energy of 500 GeV and an integrated luminosity of 500 fb−1. We also carry out the analysis assuming that both the electron and positron beams can be longitudinally polarized, and find that the sensitivity to the couplings can be improved by a factor of 2–4 by a specific choice of the signs of the polarizations of both the electron and positron beams for the same integrated luminosity.

The neutron's deep-inelastic structure functions provide essential information for the flavor separation of the nucleon parton densities, the nucleon spin decomposition, and precision studies of QCD phenomena in the flavor-singlet and nonsinglet sectors. Traditional inclusive measurements on nuclear targets are limited by dilution from scattering on protons, Fermi motion and binding effects, final-state interactions, and nuclear shadowing at x ll 0.1. An Electron-Ion Collider (EIC) would enable next-generation measurements of neutron structure with polarized deuteron beams and detection of forward-moving spectator protons over a wide range of recoil momenta (0 < p(R) < several 100MeV in the nucleus rest frame). The free neutron structure functions could be obtained by extrapolating the measured recoil momentum distributions to the on-shell point. The method eliminates nuclear modifications and can be applied to polarized scattering, as well as to semi-inclusive and exclusive final states. We review the prospects for neutron structure measurements with spectator tagging at EIC, the status of R&D efforts, and the accelerator and detector requirements.

We demonstrate the feasibility of three dimensional (3D) polarization multiplexing by optimizing a single vectorial beam using a multiple-signal window multiple-plane (MSW-MP) phase retrieval algorithm. Original messages represented with multiple quick response (QR) codes are first partitioned into a series of subblocks. Then, each subblock is marked with a specific polarization state and randomly distributed in 3D space with both longitudinal and transversal adjustable freedoms. A generalized 3D polarization mapping protocol is established to generate a 3D polarization key. Finally, multiple-QR code is encrypted into one phase only mask and one polarization only mask based on the modified Gerchberg-Saxton (GS) algorithm. We take the polarization mask as the cyphertext and the phase only mask as additional dimension of key. Only when both the phase key and 3D polarization key are correct, original messages can be recovered. We verify our proposal with both simulation and experiment evidences.

We present an experimental and theoretical study of the angle- and polarization-dependent light extinction in random arrays of polydisperse semiconductor nanowires epitaxially grown on substrates. The specular reflectance is described by averaging the scattering properties of individual nanowires obtained from Lorenz-Mie theory over the diameter distribution. The complex effective refractive index describing the propagation and attenuation of the coherent beam scattered in forward direction is determined in the independent scattering approximation and used to calculate the angle- and polarization-dependent reflectance. Our measurements demonstrate the highly anisotropic scattering in ensembles of aligned nanowires.

Optical studies of nano-objects that have dimensions 10--1000 nm have become a flourishing field of research. This special dimension category, connecting the smaller (molecular) world and the larger (cellular) world, have enabled these nano-objects to be widely utilized as novel optical tools in many fields. In addition to the extensive applications of nano objects, increasing efforts are also being put to better understand their interactions with light at a fundamental level. The work presented in this dissertation is part of such efforts, in which I selected three types of nano-objects and studied their optical properties both in theory and experiment. Second-harmonic and sum-frequency generations are among the most well-known nonlinear optical processes. Dielectric nanocrystals that are SHG- and SFG-active are favored tools in bioimaging. For a nanocrystal, its SHG/SFG intensity depends on the geometry of the light-particle system, i.e., the relationship between the nanocrystal orientation and the laser polarization. Using BaTiO 3 nanocrystals as an example, I carried out an in-depth, theoretical investigation of such dependence. Particularly, I studied the possibility of selectively maximizing the contrast between light signals from two or more nanocrystals by manipulating laser polarization. I will present a discussion on how the capacity of this selective illumination depends on the relative orientation between the two nanocrystals and the polarization of the excitation field. The optical responses of non-spherical plasmonic particles, being dynamic and complex, are only partially understood. Gold nanorods (AuNRs) are one of the most popular members in this nanoparticle family. They can produce two-photon luminescence (TPL) and amplify molecular events occurring at their surface. Both phenomena are known to be associated with surface plasmon resonances (SPR) of AuNRs, but details of the mechanisms are yet to be understood and quantified. I constructed a two

Experiments using polarized {sup 3}He atom beams to search for short range spin dependent forces are proposed. High intensity, high polarization, small beam size {sup 3}He atom beams have been successfully produced and used in surface science researches. By incorporating background reduction designs as combination shielding by μ-metal and superconductor and double beam paths, the precision of spin rotation angle per unit length could be improved by a factor of ∝ 10{sup 4}. By this precision, in combination with a high density and low magnetic susceptibility sample source mass, and reversing one beam path if necessary, sensitivities on three different types of spin dependent interactions could be improved by as much as ∝ 10{sup 2} to ∝ 10{sup 8} over the current experiments at the millimeter range. (orig.)

This lecture note reviews physics of spin motion in a synchrotron, spin depolarization mechanisms of spin resonances, and methods of overcoming the spin resonances during acceleration. Techniques used in accelerating polarized ions in the low/medium energy synchrotrons, such as the ZGS, the AGS, SATURNE, and the KEK PS and PS Booster are discussed. Problems related to polarized proton acceleration with snakes or partial snake are also examined.

Conditions for achieving equal and opposite angular deflections of a lightbeam by reflection and refraction at an air-dielectric boundary are determined. Such angularly symmetric beam splitting (ASBS) is possible only if the angle of incidence is >60° by exactly one third of the angle of refraction. This simple law, plus Snell's law, leads to several analytical results that clarify all aspects of this phenomenon. In particular, it is shown that the intensities of the two symmetrically deflected beams can be equalized by proper choice of the prism refractive index and the azimuth of incident linearly polarizedlight. ASBS enables a geometrically attractive layout of optical systems that employ multiple prism beam splitters.

Integrated polarizationbeam splitters based on birefringent directional couplers are demonstrated. The devices are fabricated in bulk fused silica glass by femtosecond laser writing (300 fs, 150 nJ at 500 kHz, 522 nm). The birefringence was measured from the spectral splitting of the Bragg grating resonances associated with the vertically and horizontally polarized modes. Polarization splitting directional couplers were designed and demonstrated with 0.5 dB/cm propagation losses and -19 dB and -24 dB extinction ratios for the polarization splitting.

Following the first experiment on three-body photodisintegration of polarized $^3$He utilizing circularly polarized photons from High Intensity Gamma Source (HI$\\gamma$S) at Duke Free Electron Laser Laboratory (DFELL), a new high-pressure polarized $^3$He target cell made of pyrex glass coated with a thin layer of sol-gel doped with aluminum nitrate nonahydrate has been built in order to reduce photon beam induced backgrounds. The target is based on the technique of spin-exchange optical pumping of hybrid rubidium and potassium and the highest polarization achieved is $\\sim$62\\% determined from both NMR-AFP and EPR polarimetry. The $X$ parameter is estimated to be $0.17\\pm0.06$ and the performance of the target is in good agreement with theoretical predictions. We also present beam test results from this new target cell and the comparison with the GE180 $^3$He target cell used previously at HI$\\gamma$S. This is the first time that sol-gel coating technique has been used in a polarized $^3$He target for nuclea...

The use of resonant depolarization has been suggested for precise beam energy measurements (better than 100 keV) in the eþe− Future Circular Collider (FCC-eþe−) for Z and WW physics at 45 and 80 GeV beam energy respectively. Longitudinal beampolarization would benefit the Z peak physics program; however it is not essential and therefore it will be not investigated here. In this paper the possibility of selfpolarized leptons is considered. Preliminary results of simulations in presence of quadrupole misalignments and beam position monitors (BPMs) errors for a simplified FCC-eþe− ring are presented.

The study of the nucleon structure has been a major research focus in fundamental physics in the past decades and still is the main research line of the Thomas Jefferson National Accelerator Facility (Jefferson Lab). For this purpose and to obtain statistically meaningful results, having both a polarizedbeam and a highly efficient polarized target is essential. For the target, this means high polarization and high relative density of polarized material. A Hydrogen Deuteride (HD) target that presents both such characteristics has been developed first at Brookhaven National Lab (BNL) and brought to the Hall B of Jefferson Lab in 2008. The HD target has been shown to work successfully under a high intensity photon beam (BNL and Jefferson Lab). However, it remained to be seen if the target could stand an electron beam of reasonably high current (nA). In this perspective, the target was tested for the first time in its frozen spin mode under an electron beam at Jefferson Lab in 2012 during the g14 experiment. This dissertation presents the principles and usage procedures of this HD target. The polarimetry of this target with Nuclear Magnetic Resonance (NMR) during the electron beam tests is also discussed. In addition, this dissertation also describes another way to perform target polarimetry with the elastic scattering of electrons off a polarized target by using data taken on helium-3 during the E97-110 experiment that occurred in Jefferson Lab's Hall A in 2003.

A polarized atomic beam source was developed for the polarized internal storage-cell gas target at the magnet spectrometer ANKE of COSY-Jülich. The intensities of the beams injected into the storage cell, measured with a compression tube, are 7.5×10{sup 16} hydrogen atoms/s (two hyperfine states) and 3.9×10{sup 16} deuterium atoms/s (three hyperfine states). For the hydrogen beam the achieved vector polarizations are p{sub z}≈±0.92. For the deuterium beam, the obtained combinations of vector and tensor (p{sub zz}) polarizations are p{sub z}≈±0.90 (with a constant p{sub zz}≈+0.86), and p{sub zz}=+0.90 or p{sub zz}=−1.71 (both with vanishing p{sub z}). The paper includes a detailed technical description of the apparatus and of the investigations performed during the development. This source has been very successfully used for single and double polarization measurements at ANKE as well as for studies of the polarization of recombining hydrogen molecules.

A 3D structured light sheet microscope using a four-faceted symmetric pyramid is presented. The sample is illuminated by the resulting four beam interference field. This approach combines advantages of standing wave and structured illumination microscopy. Examples of micrographs of fluorescently labeled Chinese hamster ovary (CHO) cells as well as of the compound eyes of drosophila are shown and the optical sectioning ability of our system is demonstrated. The capabilities and the limitations of the scheme are discussed.

Laguerre-Gaussian (LG) beams reflected from a multi-layered dielectric experience a shift in their centroid that is different than that from a single interface. This has been previously investigated for linearly polarizedbeams and, to a much lesser extent, beams with spin angular momentum. Here a combination of perturbation and computational analyses is used to provide a unified quantification of these shifts in layered dielectrics with two parallel interfaces. The approach is then extended to consider the qualitatively new behavior that results when the light is endowed with an intrinsic orbital angular momentum--i.e. vortex beams. Destructive interference causes singular lateral shifts in the centroid of the reflected vortex beam for which spin alone produces only a mild modulation. In the case of total internal reflection, both spin and intrinsic orbital angular momentum contribute to an enhancement of these lateral shifts as the interlayer thickness is decreased. This is just the opposite of the trend as...

Polarizers provide convenience in generating polarizedlight, meanwhile their adoption raises problems of extra weight, cost, and energy loss. Aiming to realize polarizer-free polarizedlight sources, herein, we present a plasmonic approach to achieve direct generation of linearly polarized optical waves at the nanometer scale. Periodic slot nanoantenna arrays are fabricated, which are driven by the transition dipole moments of luminescent semiconductor quantum dots. By harnessing interactions between quantum dots and scattered fields from the nanoantennas, spontaneous emission with a high degree of linear polarization is achieved from such hybrid antenna system with polarization perpendicular to antenna slot. We also demonstrate that the polarization is engineerable in aspects of both spectrum and magnitude by tailoring plasmonic resonance of the antenna arrays. Our findings will establish a basis for the development of innovative polarizedlight-emitting devices, which are useful in optical displays, spectroscopic techniques, optical telecommunications, and so forth.

We have studied relative-intensity fluctuations for a variable set of orthogonal elliptic polarization components of a linearly polarized laser beam traversing a resonant {sup 87}Rb vapor cell. Significant polarization squeezing at the threshold level (-3dB) required for the implementation of several continuous-variable quantum protocols was observed. The extreme simplicity of the setup, which is based on standard polarization components, makes it particularly convenient for quantum information applications.

Angular distribution of polarizedlight and its effect on light extraction efficiency (LEE) in AlGaN deep-ultraviolet (DUV) light-emitting diodes (LEDs) are investigated in this paper. A united picture is presented to describe polarizedlight's emission and propagation processes. It is found that the electron-hole recombinations in AlGaN multiple quantum wells produce three kinds of angularly distributed polarized emissions and propagation process can change their intensity distributions. By investigation the change of angular distributions in 277nm and 215nm LEDs, this work reveals that LEE can be significantly enhanced by modulating the angular distributions of polarizedlight of DUV LEDs.

Polarizedlight photography has been used to selectively differentiate surface from subsurface features of photoaged skin. Our purpose was to compare acne assessments obtained from clinical evaluations with assessments from photographs obtained with flash photography and with perpendicular polarizedlight photography. Assessments of acne with the Cunliffe scale were made of 32 subjects. Retrospective evaluations of standard and perpendicular polarizedlight photographs were made in a blinded fashion by a panel of evaluators. Visualization of inflammatory acne lesions was enhanced with perpendicular polarizedlight photography, with clear delineation of erythematous borders. Acne assessments with the use of a Cunliffe scale were significantly higher (p = 0.001) from perpendicular polarizedlight photographs than for clinical evaluations. Polarizedlight photography enhances visualization of inflammatory acne lesions in a manner not possible with conventional flash photographs, permitting accurate evaluation of the extent of disease and the effectiveness of therapy.

We report on a polarization-independent all-dielectric trapezoidal bilayer grating with broadband and high diffraction efficiency. The bilayer trapezoidal grating ridge on a reflector consists of an HfO2 layer and a SiO2 layer. The theoretical -1st order efficiencies of the grating are more than 95% with wavelength range from 1010 nm to 1080 nm for both TE and TM polarizations. The fabrication tolerances depending on the HfO2 and SiO2 layer grating ridge depths are enough to obtain the designed grating using current craft. The fabricated grating with exceeding 94% efficiency from 1000 nm to 1085 nm measured by a non-polarization laser has been fabricated and applied in a spectral beam combining external cavity to combine eight beams into one beam output with 10.77 kW.

Plasmonic antennas are able to concentrate and re-emit light in a controllable manner through strong coupling between metallic nanostructures. Only recently has it found that quantum mechanical effects can drastically change the coupling strength as the feature size approaches atomic scales. Here, we present a comprehensive experimental and theoretical study of the evolution of the resonance peak and its polarization state as the dimer-antenna gap narrows to subnanometer scale. We clearly can identify the classical plasmonic regime, a crossover regime where nonlocal screening plays an important role, and the quantum regime where a charge transfer plasmon appears due to interparticle electron tunneling. Moreover, as the gap decreases from tens of to a few nanometers, the bonding dipole mode tends to emit photons with increasing polarizability. When the gap narrows to quantum regime, a significant depolarization of the mode emission is observed due to the reduction of the charge density of coupled quantum plasmons. These results would be beneficial for the understanding of quantum effects on emitting-polarization of nanoantennas and the development of quantum-based photonic nanodevices.

Hearing loss is the most common sensory deficit in the world, and most frequently it originates in the inner ear. Yet, the inner ear has been difficult to access for diagnosis because of its small size, delicate nature, complex three-dimensional anatomy, and encasement in the densest bone in the body. Evolving optical methods are promising to afford cellular diagnosis of pathologic changes in the inner ear. To appropriately interpret results from these emerging technologies, it is important to characterize optical properties of cochlear tissues. Here, we focus on that characterization using quantitative polarizedlight microscopy (qPLM) applied to unstained cochlear sections of the mouse, a common animal model of human hearing loss. We find that the most birefringent cochlear materials are collagen fibrils and myelin. Retardance of the otic capsule, the spiral ligament, and the basilar membrane are substantially higher than that of other cochlear structures. Retardance of the spiral ligament and the basilar membrane decrease from the cochlear base to the apex, compared with the more uniform retardance of other structures. The intricate structural details revealed by qPLM of unstained cochlear sections ex vivo strongly motivate future application of polarization-sensitive optical coherence tomography to human cochlea in vivo.

To investigate the influence of polarization on the polarizedlight propagation in biological tissue, a polarized geometric Monte Carlo method is developed. The Stokes-Mueller formalism is expounded to describe the shifting of lightpolarization during propagation events, including scattering and interface interaction. The scattering amplitudes and optical parameters of different tissue structures are obtained using Mie theory. Through simulations of polarizedlight (pulsed dye laser at wavelength of 585 nm) propagation in an infinite slab tissue model and a discrete vessel tissue model, energy depositions in tissue structures are calculated and compared with those obtained through general geometric Monte Carlo simulation under the same parameters but without consideration of polarization effect. It is found that the absorption depth of the polarizedlight is about one half of that determined by conventional simulations. In the discrete vessel model, low penetrability manifests in three aspects: diffuse reflection became the main contributor to the energy escape, the proportion of epidermal energy deposition increased significantly, and energy deposition in the blood became weaker and more uneven. This may indicate that the actual thermal damage of epidermis during the real-world treatment is higher and the deep buried blood vessels are insufficiently damaged by consideration of polarization effect, compared with the conventional prediction.

Full Text Available By means of the state-of-the-art reactive oxide molecular beam epitaxy, we synthesized (001- and (111-orientated polar LaNiO3 thin films. In order to avoid the interfacial reconstructions induced by polar catastrophe, screening metallic Nb-doped SrTiO3 and iso-polarity LaAlO3 substrates were chosen to achieve high-quality (001-orientated films in a layer-by-layer growth mode. For largely polar (111-orientated films, we showed that iso-polarity LaAlO3 (111 substrate was more suitable than Nb-doped SrTiO3. In situ reflection high-energy electron diffraction, ex situ high-resolution X-ray diffraction, and atomic force microscopy were used to characterize these films. Our results show that special attentions need to be paid to grow high-quality oxide films with polar orientations, which can prompt the explorations of all-oxide electronics and artificial interfacial engineering to pursue intriguing emergent physics like proposed interfacial superconductivity and topological phases in LaNiO3 based superlattices.

By means of the state-of-the-art reactive oxide molecular beam epitaxy, we synthesized (001)- and (111)-orientated polar LaNiO3 thin films. In order to avoid the interfacial reconstructions induced by polar catastrophe, screening metallic Nb-doped SrTiO3 and iso-polarity LaAlO3 substrates were chosen to achieve high-quality (001)-orientated films in a layer-by-layer growth mode. For largely polar (111)-orientated films, we showed that iso-polarity LaAlO3 (111) substrate was more suitable than Nb-doped SrTiO3. In situ reflection high-energy electron diffraction, ex situ high-resolution X-ray diffraction, and atomic force microscopy were used to characterize these films. Our results show that special attentions need to be paid to grow high-quality oxide films with polar orientations, which can prompt the explorations of all-oxide electronics and artificial interfacial engineering to pursue intriguing emergent physics like proposed interfacial superconductivity and topological phases in LaNiO3 based superlattices.

We present a theoretical analysis of the Thomson scattering of linearly and circularly polarized photons from a pulsed laser by electrons. The analytical expression for the photon distribution functions presented in this paper should be useful to designers of Thomson scattering experiments.

Contact-like nonstandard interactions can be revealed only through deviations of observables from the standard model (SM) predictions. We consider a number of such nonstandard scenarios, and discuss their identification as sources of deviations in fermion-pair production processes at the international linear collider (ILC), if they were observed. We emphasize the role of - and + polarization in enhancing the identification reaches.

Circularly polarizedlight is rare in the terrestrial environment, and cuticular reflections from scarab beetles are one of the few natural sources. Chrysina gloriosa LeConte 1854, a scarab beetle found in montane juniper forests of the extreme southwestern United States and northern Mexico, are camouflaged in juniper foliage; however, when viewed with right circularly polarizing filters, the beetles exhibit a stark black contrast. Given the polarization-specific changes in the appearance of C. gloriosa, we hypothesized that C. gloriosa can detect circularly polarizedlight. We tested for phototactic response and differential flight orientation of C. gloriosa toward different light stimuli. Chrysina gloriosa exhibited (a) positive phototaxis, (b) differential flight orientation between linear and circularly polarizedlight stimuli of equal intensities, and (c) discrimination between circularly polarized and unpolarized lights of different intensities consistent with a model of circular polarization sensitivity based on a quarter-wave plate. These results demonstrate that C. gloriosa beetles respond differentially to circularly polarizedlight. In contrast, Chrysina woodi Horn 1885, a close relative with reduced circularly polarized reflection, exhibited no phototactic discrimination between linear and circularly polarizedlight. Circularly polarized sensitivity may allow C. gloriosa to perceive and communicate with conspecifics that remain cryptic to predators, reducing indirect costs of communication.

Optical cone beam computed tomography (CBCT) using a broad beam and CCD camera is a fast method for densitometry of 3D optical gel dosimeters. However, diffuse light sources introduce considerable stray light into the imaging system, leading to underestimation of attenuation coefficients and non-uniformities in CT images unless corrections are applied to each projection image. In this study, the light source of a commercial optical CT scanner is replaced with a convergent cone beam source consisting of almost exclusively image forming primary rays. The convergent source is achieved using a small isotropic source and a Fresnel lens. To characterize stray light effects, full-field cone beam CT imaging is compared to fan beam CT (FBCT) using a 1 cm high fan beam aperture centered on the optic axis of the system. Attenuating liquids are scanned within a large 96 mm diameter uniform phantom and in a small 13.5 mm diameter finger phantom. For the uniform phantom, cone and fan beam CT attenuation coefficients agree within a maximum deviation of (1 ± 2)% between mean values over a wide range from 0.036 to 0.43 cm(-1). For the finger phantom, agreement is found with a maximum deviation of (4 ± 2)% between mean values over a range of 0.1-0.47 cm(-1). With the convergent source, artifacts associated with refractive index mismatch and vessel optical features are more pronounced. Further optimization of the source size to achieve a balance between quantitative accuracy and artifact reduction should enable practical, accurate 3D dosimetry, avoiding time consuming 3D scatter measurements.

Optical cone beam computed tomography (CBCT) using a broad beam and CCD camera is a fast method for densitometry of 3D optical gel dosimeters. However, diffuse light sources introduce considerable stray light into the imaging system, leading to underestimation of attenuation coefficients and non-uniformities in CT images unless corrections are applied to each projection image. In this study, the light source of a commercial optical CT scanner is replaced with a convergent cone beam source consisting of almost exclusively image forming primary rays. The convergent source is achieved using a small isotropic source and a Fresnel lens. To characterize stray light effects, full-field cone beam CT imaging is compared to fan beam CT (FBCT) using a 1 cm high fan beam aperture centered on the optic axis of the system. Attenuating liquids are scanned within a large 96 mm diameter uniform phantom and in a small 13.5 mm diameter finger phantom. For the uniform phantom, cone and fan beam CT attenuation coefficients agree within a maximum deviation of (1 ± 2)% between mean values over a wide range from 0.036 to 0.43 cm-1. For the finger phantom, agreement is found with a maximum deviation of (4 ± 2)% between mean values over a range of 0.1-0.47 cm-1. With the convergent source, artifacts associated with refractive index mismatch and vessel optical features are more pronounced. Further optimization of the source size to achieve a balance between quantitative accuracy and artifact reduction should enable practical, accurate 3D dosimetry, avoiding time consuming 3D scatter measurements.

We show that the polarization state of coherent light propagating through an optically thick multiple-scattering medium, can be controlled by wavefront shaping, i.e. by controlling only the spatial phase of the incoming field with a spatial light modulator. Any polarization state of light at any spatial position behind the scattering medium can be attained with this technique. Thus, transforming the random medium to an arbitrary optical polarization component becomes possible.

The internal energy flow in a lightbeam can be divided into the "orbital" and "spin" parts, associated with the spatial and polarization degrees of freedom of light. In contrast to the orbital one, experimental observation of the spin flow seems problematic because it is converted into an orbital...... particles within a field where the transverse energy circulation is associated exclusively with the spin flow. This result can be treated as the first demonstration of mechanical action of the spin flow of a light field....

In a number of papers an attractive method of laser polarization of electrons (positrons) at storage rings or linear colliders have been proposed. We show that these suggestions are incorrect and based on errors in simulation of multiple Compton scattering and in calculation of the Compton spin-flip cross sections. We argue that the equilibrium polarization in this method is zero.

If the recent PVLAS results on polarization changes of a linearly polarized laser beam passing through a magnetic field are interpreted by an axion-like particle, it is almost certain that it is not a standard QCD axion. Considering this, we study the general effective interactions of photons with spin-zero particles without restricting the latter to be a pseudo-scalar or a scalar, i.e., a parity eigenstate. To lowest order in effective field theory, there are two dimension-5 interactions, each of which has previously been treated separately for a pseudo-scalar or a scalar particle. By following the evolution in an external magnetic field of the system of spin-zero particles and photons, we compute the changes of lightpolarization and the transition probability for two experimental set-ups: one-way propagation and round-trip propagation. While the first may be relevant for astrophysical sources of spin-zero particles, the second applies to laboratory optical experiments like PVLAS. We find that interference ...

We propose a beam splitter for cold polar molecules in weak-field-seeking states that uses a Y-shaped charged wire half embedded in a substrate and sandwiched by a charged metallic parallel-plate capacitor. We demonstrate our molecular-beam splitter and study its dynamic beam-splitting process for the guided cold molecules by using Monte Carlo simulation. Our study shows that cold polar molecules from a supersonic beam source with a mean velocity of a few hundred meters per second can be split with a fixed 0.5/0.5 splitting ratio, and an adjustable splitting ratio of about 0.03-0.97 can be realized by introducing a small alteration to the scheme.

The propagation of an electron beam in the presence of transverse magnetic fields possessing integer topological charges is presented. The spin–magnetic interaction introduces a nonuniform spin precession of the electrons that gains a space-variant geometrical phase in the transverse plane proportional to the field's topological charge, whose handedness depends on the input electron's spin state. A combination of our proposed device with an electron orbital angular momentum sorter can be utilized as a spin-filter of electron beams in a mid-energy range. We examine these two different configurations of a partial spin-filter generator numerically. The results of this analysis could prove useful in the design of an improved electron microscope. - Highlights: • Theory of generating spin-polarized electron beams. • Interacting electron vortex beams with space-variant magnetic fields. • Bohr–Pauli impossibility of generating spin-polarized free electrons.

In this contribution accelerator solutions for polarizedbeams and their impact on physics measurements are discussed. Focus are physics requirements for precision polarimetry near the interaction point and their realization with polarized sources. Based on the ILC baseline programme as described in the Reference Design Report (RDR), recent developments are discussed and evaluated taking into account physics runs at beam energies between 100 GeV and 250 GeV, as well as calibration runs on the Z-pole and options as the 1 TeV upgrade and GigaZ. (orig.)

We propose a DC-based polarizationbeam splitter (PBS) in lithium niobate on insulator (LNOI). Utilizing the high birefringence property of Lithium Niobate (LiNbO3, LN), the device is achieved by simple structure in a short length. With the use of beam propagation method (BPM), the simulation results show that the device has a good performance for the separation of TE and TM polarizations with a high extinction ratio (about 35 dB). The simulated fabrication tolerance for the variation of the waveguide width is about 100 nm and the bandwidth is about 65 nm when the extinction ratio is higher than 10 dB.

A radially polarizedbeam with an annular intensity pattern was generated through a second-harmonic-generation process by focusing an azimuthally polarized Ti:sapphire pulsed laser beam to a c-cut beta-barium borate (BBO) crystal. The annular intensity pattern of the second-harmonic wave had a nearly sixfold symmetry as a result of the nonlinear susceptibility tensor of the BBO crystal. The width of the annulus was as narrow as less than 1/40th of its radius.

A high index dielectric nano-sphere can be excited and yet remain radiationless. A method to excite the non-radiating anapole mode of a high index isotropic dielectric nanosphere is presented. With tightly focused radially polarizedbeam illumination, the main-contributing electric dipole mode and magnetic modes can be zero with only a weak electric quadruple contributing to the total scattering. Further, with a standing wave illumination formed by two counter-propagating focused radially polarizedbeam under $4\\pi$ configuration, the ideal radiationless ananpole can be excited.

We overcome several thermal issues present in Ho:YAG lasers by distributing the gain over a larger volume and achieve a diffraction-limited beam using coherent polarization locking. Increased single-pass absorption, suppression of output power saturation, and improvement in beam quality were shown using the coherent polarization locking technique as compared to a conventional Ho:YAG laser cavity with the same pump and cavity configuration. Ten watts of CW Ho:YAG laser power was generated with >96% coherent combining efficiency.

A photonic crystal polarizationbeam splitter based on the self-collimation effect is proposed. By means of the plane wave expansion method and the finite-difference time-domain method, we analyse the splitting mechanism in two alternative ways: performing a band gap structure analysis and simulating the field distribution. The results indicate that two beams of different polarizations can be split with an extinction ratio of nearly 20 dB in a wavelength range of 90nm. The splitter may have practical applications in integrated photonic circuits.

The electrostatic slow-positron beam is constructed by using {sup 22}Na source. We design the electrostatic lens, the system of the detector, and the Wien filter for the experiment`s system of the spin-polarized slow positron beam. The reemitted spin-polarized slow-positron spectroscopy is proposed for studying magnetic thin films and magnetic multilayers. We calculated the depolarized positron fractions in the Fe thin film Fe(10nm)/Cu(substrate) and the multilayers Cu(1nm)/Fe(10nm)/Cu(substrate). (author)

An rf solenoid was operated in the IUCF Cooler to induce a depolarizing spin resonance for a stored polarized deuteron beam. The decay lifetimes of the vector and tensor polarizations were found to be in the ratio $1.9:1$, as opposed to the expected ratio of $3:1$ from standard angular momentum theory. This report describes my investigations and attempts to formulate a theoretical explanation of the above phenomenon.

Effective polarimetry at high energies in hadron and lepton synchrotrons has been a long-standing and difficult problem. In synchrotrons with polarizedbeams it is possible to cause the direction of the polarization vector of a given bunch to alternate at a frequency which is some subharmonic of the rotation frequency. This can result in the presence of lines in the beam spectrum which are due only to the magnetic moment of the beam and which are well removed from the various lines due to the charge of the beam. The magnitude of these lines can be calculated from first principles. They are many orders of magnitude weaker than the Schottky signals. Measurement of the magnitude of one of these lines would be an absolute measurement of beampolarization. For measuring magnetic field, the Superconducting Quantum Interference Device, or squid, is about five orders of magnitude more sensitive than any other transducer. Using a squid, such a measurement might be accomplished with the proper combination of shielding, pickup loop design, and filtering. The resulting instrument would be fast, non-destructive, and comparatively cheap. In addition, techniques developed in the creation of such an instrument could be used to measure the Schottky spectrum in unprecedented detail. We present specifics of a polarimeter design for the Relativistic Heavy Ion Collider (RHIC) and briefly discuss the possibility of using this technique to measure polarization at high-energy electron machines like LEP and HERA. {copyright} {ital 1997 American Institute of Physics.}

In the e/sup +/e/sup -/ -> e/sup +/e/sup -/..gamma.. process at LEP, impact parameters occur which are larger then the transverse beam sizes. This decreases considerably the number of observed photons compared to standard QED calculation. Fortunately, the measurement of the longitudinal beampolarization is practically not influenced by this effect. The possibility to use double bremsstrahlung for monitoring is discussed as well.

Under the approximation of small birefringence, the properties of circalarly polarized vortex beams tightly focused through a uniaxial birefringent crystal are studied. With the proper combination of the topological charge and the birefringence, the small focus, the small bottle beam and the inverse c-shaped intensity profile can be obtained.The effects of the focal shift and the Strehl ratio on the birefringence are analysed. A relation between angular momentum (included spin and orbital) and topological Pancharatnam charge is also presented.

While SUSY particles, if they exist at the TeV-scale, will be discovered at the Tevatron or the LHC, the determination of the SUSY-breaking scenario and its free parameters will require additional information, e.g. from a future International Linear Collider. We point out that such information, in particular on SUSY-particle mixing and the associated soft SUSY-breaking parameters, can also be obtained from measurements at existing or future polarized hadron colliders, since the polarization of initial-state quarks, transmitted through weak gauge bosons or squarks, can be strongly correlated with the helicity and gaugino/higgsino mixing of final-state sleptons, squarks, neutralinos and charginos.

While SUSY particles, if they exist at the TeV-scale, will be discovered at the Tevatron or the LHC, the determination of the SUSY-breaking scenario and its free parameters will require additional information, e.g. from a future International Linear Collider. We point out that such information, in particular on SUSY-particle mixing and the associated soft SUSY-breaking parameters, can also be obtained from measurements at existing or future polarized hadron colliders, since the polarization of initial-state quarks, transmitted through weak gauge bosons or squarks, can be strongly correlated with the helicity and gaugino/higgsino mixing of final-state sleptons, squarks, neutralinos and charginos.

It is shown that the vector-vortex Laguerre-Gauss modes with polarization-orbital angular momentum (OAM) entanglement are the vector solutions of the Maxwell equations in a graded-index medium. Focusing of linearly and circularly polarized vortex lightbeams with nonzero azimuthal and radial indices in a cylindrical graded-index waveguide is investigated. The wave shape variation with distance taking into account the spin-orbit and nonparaxial effects is analyzed. The effect of long-term periodic revival of wave packets due to mode interference in a graded-index cylindrical optical waveguide is demonstrated. High efficiency transfer of a strongly focused spot through an optical waveguide over large distances takes place with a period of revival.

We describe digital beam deflectors (DBDs) based on liquid crystals. Each stage of the device comprises a polarization rotator and a birefringent prism deflector. The birefringent prism deflects the beam by an angle that depends on polarization of the incident beam. The prism can be made of the uniaxial smectic A (SmA) liquid crystal (LC) or a solid crystal such as yttrium orthovanadate (YVO4). SmA prisms have high birefringence and can be constructed in a variety of shapes, including single prisms and prismatic blazed gratings of different angles and profiles. We address the challenges of uniform alignment of SmA, such as elimination of focal conic domains. Rotation of linear polarization is achieved by an electrically switched twisted nematic (TN) cell. A DBD composed of N rotator-deflector pairs steers the beam into 2(sup N) directions. As an example, we describe a four-stage DBD deflecting normally incident laser beam within the range of +/- 56 mrad with 8 mrad steps. Redirection of the beam is achieved by switching the TN cells.

The annular photonic crystals have been regarded as a satisfactory candidate to realize dual-polarization photonic device. In this letter, we focus our attention on the study of annular photonic crystal cavity to verify its application in light emission. We proposed a two-dimensional photonic crystal model with annular air units and a point-line defect to construct a cavity for the enhancement of light emission of InAs quantum dots. With the help of global optimization method, we have obtained an annular photonic crystal cavity design which can show a high in-plane quality factor of about 1.3*105 and 2.8*106 for transverse electric and transverse magnetic polarizations, respectively. Based on the Electron Beam Lithography and Reactive Ion Etching techniques, such cavity pattern was transferred into the top of InAs/GaAs active layer. The photoluminescence spectra of sample demonstrated clear light emission at around 1.3 um for both polarizations. Such dual-polarizationlight emitter has potential applications ...

We demonstrate an all-optical (4)He atomic magnetometer experimental scheme based on an original Bell-Bloom configuration. A single intensity-modulated linearly polarized laser beam is used both for generating spin polarization within a single (4)He vapor and probing the spin precessing under a static magnetic field. The transmitted light signal from the vapor is then phase-sensitively detected at the modulation frequency and its harmonics, which lead to the atomic magnetic resonance signals. Based on this structure, a liquid crystal is added in our magnetometer system and constitutes a polarization rotator. By controlling the voltage applied on the liquid crystal, the light linear polarization vector can be kept perpendicular with the ambient magnetic field direction, which in turn provides the maximum resonance signal amplitude. Moreover, the system exhibits a magnetic-field noise floor of about 2pT/√Hz, which is not degraded due to the presence of the liquid crystal and varying magnetic field direction. The experiment results prove that our method can eliminate the dead-zone effect, improve the system spatial isotropy, and thus be suitable in mobile applications.

Proposed herein is an alternative photonic scheme for the generation of a doublet UWB pulse, which is based on the nonlinear polarization rotation of an elliptically polarized probe beam. The proposed scheme is a modified optical-fiber Kerr shutter that uses an elliptically polarized probe beam together with a linearly polarized control beam. Through theoretical analysis, it was shown that the optical-fiber-based Kerr shutter is capable of producing an ideal transfer function for the successful conversion of input Gaussian pulses into doublet pulses under special elliptical polarization states of the probe beam. An experimental verification was subsequently carried out to verify the working principle. Finally, the system performance of the generated UWB doublet pulses was assessed by propagating them over a 25-km-long standard single-mode fiber link, followed by wireless transmission. Error-free transmission was successfully achieved.

The polarization and orbital angular momentum properties of light are of great importance in optical science and technology in the fields of high precision optical measurements and high capacity and high speed optical communications. Here we show, a totally new method, based on a combination of these two properties and using the thermal dispersion and electro-optical effect of birefringent crystals, the construction of a simple and robust scheme to rotate a lightbeam like a fan. Using a computer-based digital image processing technique, we determine the temperature and the thermal dispersion difference of the crystal with high resolution. We also use the rotation phenomenon to realize thermo-optic and electro-optic switches. The basic operating principles for measurement and switching processes are presented in detail. The methods developed here will have wide practical applicability in various fields, including remote sensing, materials science and optical communication networks.

Single attosecond pulse generation with polarization gating Bessel-Gauss beam in relatively strongly-ionized media is investigated. The results show that Bessel-Gauss beam has the ability to suppress the spatial plasma dispersion effects caused by high density of free electrons, thus the laser field can maintain its spatial profile through highly-ionized medium. This indicates the use of Bessel-Gauss beam has advantages over Gaussian beam in high harmonic generation under high ionization conditions. In our scheme, significant improvement of spatiotemporal properties of harmonics is achieved and an isolated attosecond pulse with high beam quality is filtered out using polarization gating.

This work describes a new method using polarizedlight microscopy to determine the failure modes of fractured beams following microtensile bond strength testing. The outcomes were validated using SEM and EDX elemental analysis. Resin adhesives and resin composites bonded to caries-free dentin samples as well as disks of adhesive and composite were observed with reflected polarizedlight microscopy (PLM) to obtain standard images. A set of beams fractured in the microtensile bond test were observed with PLM and compared with the standard images to determine failure mode through PLM color matching with the standard dentin, adhesive, or composite images. Samples were analyzed by EDX under SEM and compared with the PLM outcomes. Reflected PLM images showed that the fractured surfaces covered with resin-based materials (adhesives or composite) appeared pink in color, in contrast to dentin surfaces, which appeared yellow. EDX mapping together with SEM observation confirmed the results obtained by PLM. The results of EDX mapping and SEM observation showed that the use of polarizedlight microscopy is a simple, viable method for differentiation between the resin-covered dentin surfaces for determining fracture pattern analysis after bond testing.

We report a technique for encoding both amplitude and phase variations onto a laser beam using a single digital micro-mirror device (DMD). Using this technique, we generate Laguerre-Gaussian and vortex orbital-angular-momentum (OAM) modes, along with modes in a set that is mutually unbiased with respect to the OAM basis. Additionally, we have demonstrated rapid switching among the generated modes at a speed of 4 kHz, which is much faster than the speed regularly achieved by phase-only spatial light modulators (SLMs). The dynamic control of both phase and amplitude of a laser beam is an enabling technology for classical communication and quantum key distribution (QKD) systems that employ spatial mode encoding.

In the context of the space-based nulling mission ESA-Darwin, Thales Alenia Space has developed a nulling breadboard for the European Space Agency (ESA): the multiaperture imaging interferometer (MAII) to demonstrate deep and stable nulling and to investigate various subsystems of the ESA-Darwin interferometer. Recently, we have extended our investigations to the multiaxial beam combination. This combination scheme presents many advantages: simplicity, compactness, and a high coupling efficiency for a three-beam combination. The near-infrared (lambda approximately 1.55 microm) MAII breadboard has been upgraded to the multiaxial beam combination. Polarization and stability issues have been thoroughly investigated. We report on the recent results we have obtained with the multiaxial configuration of MAII in unpolarized light with a relative spectral bandwidth of 5%: nulling ratios of mean value N=1.7 x 10(-5), stable over 1 h with a standard deviation sigma( N )=5.7 x 10(-7). These results indicate that the multiaxial beam combination has the potential to meet Darwin requirements.

Unpolarized instrumentation has long been studied and designed using McStas simulation tool. But, only recently new models were developed for McStas to simulate polarized neutron scattering instruments. In the present contribution, we used McStas software to design a polarized neutron beam line, taking advantage of the available spectrometers reflectometer and diffractometer in Algeria. Both thermal and cold neutron was considered. The polarization was made by two types of supermirrors polarizers FeSi and CoCu provided by the HZB institute. For sake of performance and comparison, the polarizers were characterized and their characteristics reproduced. The simulated instruments are reported. Flipper and electromagnets for guide field are developed. Further developments including analyzers and upgrading of the existing spectrometers are underway.

Digital optical phase conjugation (DOPC) is an emerging technique for focusing light through or within scattering media such as biological tissue. Since DOPC systems are based on time reversal, they benefit from collecting as much information about the scattered light as possible. However, existing DOPC techniques record and subsequently phase-conjugate the scattered light in only a single-polarization state, limited by the operating principle of spatial light modulators. Here, we develop the first, to the best of our knowledge, full-polarization DOPC system that records and phase-conjugates scattered light along two orthogonal polarizations. When focusing light through thick scattering media, such as 2 mm and 4 mm-thick chicken breast tissue, our full-polarization DOPC system on average doubles the focal peak-to-background ratio achieved by single-polarization DOPC systems and improves the phase-conjugation fidelity.

Around 1999, thanks to the RHIC Spin Collaboration (RSC), the Relativistic Heavy Ion Collider (RHIC) will be used as a polarized proton-proton collider. A new handed interaction between quark subconstituents, which could explain the excess of large E_T jet found by the CDF collaboration, could be at the origin of some small parity violating effects in one-jet inclusive production. Using spin asymmetries it is possible, at RHIC, to disentangle this new effect from the Standard Model prediction due to QCD-ElectroWeak interferences.

It is shown that all optical polarization states of light except plane and circular polarization states undergo an intensity-dependent change in normal incidence of light in an isotropic nonlinear Kerr medium. This effect should be detectable and we propose an experiment for detecting nonlinear susceptibility involved in that part of nonlinear polarization, which depends on the polarization state of light also.

Polarization measurements of the primary X-ray beam produced by thick copper and tungsten anodes are reported and formulas derived for integrated intensities of Bragg reflections in energy-dispersive diffractometry with the polarization of the primary beam taken into account. It was found...

In a recent article [R. R. Alfano and D. A. Nolan, Opt. Commun. 361 (2016) 25] the group velocity reduction below the speed of light in the case of certain Bessel beam pulses has been considered and an idea of its application for a natural optical buffer presented. However, the authors treat the problem as if only one type of Bessel pulse existed, no matter how it is generated. The deficiencies of the article stem from not being familiar with an extensive literature on Bessel pulses, in particular, with a couple of papers published much earlier in the J. Opt. Soc. Am. A, which have studied exactly the same problem more thoroughly.

The meiotic spindle in the oocyte is composed of microtubules and plays an important role during chromosome alignment and separation at meiosis. Polarizedlight microscopy (PLM) could be useful for a non-invasive evaluation of the meiotic spindle and may allow removal of nuclear structures without fluorochrome staining and ultraviolet exposure. In this study, PLM was used to assess its potential application in porcine reproductive technologies. The objectives of the present study were to assess the efficiency of PLM to detect microtubule-polymerized protein in in vitro-matured porcine oocytes; to examine its effects on the oocyte developmental competence; to select oocytes based on the presence of the meiotic spindle detected by PLM; and to assess the efficiency oocyte enucleation assisted with PLM. In the first experiment, the presence of microtubule-polymerized protein was assessed and confirmed in oocytes (n = 117) by immunostaining and chromatin detection. In the second experiment, oocytes (n = 160) were exposed or not (controls) to PLM for 10 minutes, and then parthenogenetically activated and cultured in vitro. In the third experiment, development competence of oocytes with a positive or negative signal to PLM was analyzed after in vitro fertilization. Finally, oocytes (n = 54) were enucleated using PLM as a tool to remove the meiotic spindle. A positive PLM signal was detected in 98.2 % of the oocytes, which strongly correlated (r = 1; p PLM did not differ significantly from controls on cleavage, total blastocyst, expanded blastocyst rates and total cell numbers. The percentage of oocytes at the MII stage and blastocyst formation rate in the negative PLM group significantly differed from control and PLM positive groups. Overall efficiency of spindle removal using the PLM-Oosight system was 92.6%. These results suggest that polarizedlight microscopy is an efficient system to detect microtubule-polymerized protein in in vitro-matured porcine oocytes and does

With this proposal we request beam time for the first two phases of a project that aims at measuring the $\\beta$-asymmetry parameter of the mirror $\\beta$-decay branch in $^{35}$Ar using an optically polarized Ar atom beam. The final goal of the experiment is to measure this parameter to a precision of 0.5%. This will allow the most precise determination of the V$_{ud}$ quark mixing matrix element from all the mirror transitions with an absolute uncertainty of 0.0007. The proposal will be presented in phases and we ask here 11 shifts (7 on-line + 4 off-line) for phase 1 and 15 shifts (6 on-line and 9 off-line) for phase 2. Phase 1 aims at establishing the optimal laser polarization scheme as well as the best implantation host for maintaining the polarization. Phase 2 aims at enhancing the beampolarization by removing the unpolarized part of the beam using re-ionization.

Full Text Available Massive multiple input, multiple output (M-MIMO technologies have been proposed to scale up data rates reaching gigabits per second in the forthcoming 5G mobile communications systems. However, one of crucial constraints is a dimension in space to implement the M-MIMO. To cope with the space constraint and to utilize more flexibility in 3D beamforming (3D-BF, we propose antenna polarization in M-MIMO systems. In this paper, we design a polarized M-MIMO (PM-MIMO system associated with 3D-BF applications, where the system architectures for diversity and multiplexing technologies achieved by polarized 3D beams are provided. Different from the conventional 3D-BF achieved by planar M-MIMO technology to control the downtilted beam in a vertical domain, the proposed PM-MIMO realizes 3D-BF via the linear combination of polarizedbeams. In addition, an effective array selection scheme is proposed to optimize the beam-width and to enhance system performance by the exploration of diversity and multiplexing gains; and a blind channel estimation (BCE approach is also proposed to avoid pilot contamination in PM-MIMO. Based on the Long Term Evolution-Advanced (LTE-A specification, the simulation results finally confirm the validity of our proposals.

We present an analysis of the phase and amplitude responses of guided resonances in a photonic crystal slab. Through this analysis, we obtain the general rules and conditions under which a photonic crystal slab can be employed as a general elliptical polarizationbeam splitter, separating an incoming beam equally into its two orthogonal constituents, so that half the power is reflected in one polarization state, and half the power is transmitted in the other state. We show that at normal incidence a photonic crystal slab acts as a dual quarter-wave retarder in which the fast and slow axes are switched for reflection and transmission. We also analyze the case where such a structure operates at oblique incidences. As a result we show that the effective dielectric constant of the photonic crystal slab imposes the Brewster angle as a boundary, separating two ranges of angles with different mechanisms of polarizationbeam splitting. We show that the diattenuation can be tuned from zero to one to make the structure a circular or linear polarizationbeam splitter. We verify our analytical analysis through finite-difference time-domain simulations and experimental measurements at infrared wavelengths.

We analyze the impact of electron and positron beampolarization on radiative neutralino production at the International Linear Collider (ILC). We focus on three different mSUGRA scenarios in turn at the Higgs strahlung threshold, the top pair production threshold, and at $\\sqrt{s} =500\\GeV$. In these scenarios at the corresponding $\\sqrt{s}$, radiative neutralino production is the only supersymmetric production mechanism which is kinematically allowed. The heavier neutralinos, and charginos as well as the sleptons, squarks and gluinos are too heavy to be pair produced. We calculate the signal cross section and also the Standard Model background from radiative neutrino production. For our scenarios, we obtain significances larger than 10 and signal to background ratios between 2% and 5%, if we have electron beampolarization $P_{e^-} = 0.0- 0.8$ and positron beampolarization $P_{e^+} = 0.0 - 0.3$. If we have electron beampolarization of $P_{e^-} = 0.9$, then the signal is observable with $P_{e^+} = 0.0$ but...

We analyze the impact of electron and positron beampolarization on radiative neutralino production at the international linear collider (ILC). We focus on three different mSUGRA scenarios in turn at the Higgsstrahlung threshold, the top pair production threshold, and at {radical}(s)=500 GeV. In these scenarios at the corresponding {radical}(s), radiative neutralino production is the only supersymmetric production mechanism that is kinematically allowed. The heavier neutralinos and charginos as well as the sleptons, squarks and gluinos are too heavy to be pair produced. We calculate the signal cross section and also the standard model background from radiative neutrino production. For our scenarios, we obtain significances larger than 10 and signal to background ratios between 2% and 5%, if we have electron beampolarization P{sub e}{sup -}=0.0-0.8 and positron beampolarization P{sub e}{sup +}=0.0-0.3. If we have electron beampolarization of P{sub e}{sup -}=0.9, then the signal is observable with P{sub e}{sup +}=0.0 but both the significance and the signal to background ratio are significantly improved for P{sub e}{sup +}=0.3. (orig.)

We analyze the impact of electron and positron beampolarization on radiative neutralino production at the international linear collider (ILC). We focus on three different mSUGRA scenarios in turn at the Higgs strahlung threshold, the top pair production threshold, and at sqrt{s} =500 GeV. In these scenarios at the corresponding sqrt{s}, radiative neutralino production is the only supersymmetric production mechanism that is kinematically allowed. The heavier neutralinos and charginos as well as the sleptons, squarks and gluinos are too heavy to be pair produced. We calculate the signal cross section and also the standard model background from radiative neutrino production. For our scenarios, we obtain significances larger than 10 and signal to background ratios between 2% and 5%, if we have electron beampolarization P_{e^-} = 0.0 0.8 and positron beampolarization P_{e^+} = 0.0 0.3. If we have electron beampolarization of P_{e^-} = 0.9, then the signal is observable with P_{e^+} = 0.0 but both the significance and the signal to background ratio are significantly improved for P_{e^+} = 0.3.

The formulation of the interaction of matter with singular light fields needs special care. In a recent article [Phys.~Rev.~A {\\bf 91}, 033808 (2015)] we have shown that the Hamiltonian describing the interaction of a twisted lightbeam having parallel orbital and spin angular momenta with a small object located close to the phase singularity can be expressed only in terms of the electric field of the beam. Here, we complement our studies by providing an interaction Hamiltonian for beams having antiparallel orbital and spin angular momenta. Such beams may exhibit unusually strong magnetic effects. We further extend our formulation to radially and azimuthally polarizedbeams. The advantages of our formulation are that for all beams the Hamiltonian is written solely in terms of the electric and magnetic fields of the beam and as such it is manifestly gauge-invariant. Furthermore it is intuitive by resembling the well-known expressions in the dipole-electric and dipole-magnetic moment approximations.

We present observations of polar mesospheric summer echoes (PMSE) using the Middle Atmosphere Alomar Radar System in Northern Norway (69.30° N, 16.04° E). The radar is able to resolve PMSE at high spatial and temporal resolution and to perform pulse-to-pulse beam steering. In this experiment, 81 oblique beam directions were used with off-zenith angles up to 25°. For each beam pointing direction and range gate, coherent radar imaging was applied to determine the mean backscatter location. The location of the mean scatterer in the beam volume was calculated by the deviation from the nominal off-zenith angle of the brightest pixel. It shows that in tilted beams with an off-zenith angle greater than 5°, structures appear at the altitudinal edges of the PMSE layer. Our results indicate that the mean influence of the location of the maximum depends on the tilt of the beam and on the observed area of the PMSE layer. At the upper/lower edge of the PMSE layer, the mean backscatter has a greater/smaller off-zenith angle than the nominal off-zenith angle. This effect intensifies with greater off-zenith beam pointing direction, so the beam filling factor plays an important role in the observation of PMSE layers for oblique beams.

Imprinting of anisotropic structures on the silicon surface by double pulse femtosecond laser irradiation is demonstrated. The origin of the polarization-induced anisotropy is explained in terms of interaction of linearly polarized second pulse with the wavelength-sized symmetric crater-shaped structure generated by the linearly polarized first pulse. A wavefront sensor is fabricated by imprinting an array of micro-craters. Polarization controlled anisotropy of the structures can be also explored for data storage applications.

Inspired by the classical phenomenon of random walk, the concept of quantum walk has emerged recently as a powerful platform for the dynamical simulation of complex quantum systems, entanglement production and universal quantum computation. Such a wide perspective motivates a renewing search for efficient, scalable and stable implementations of this quantum process. Photonic approaches have hitherto mainly focused on multi-path schemes, requiring interferometric stability and a number of optical elements that scales quadratically with the number of steps. Here we report the experimental realization of a quantum walk taking place in the orbital angular momentum space of light, both for a single photon and for two simultaneous indistinguishable photons. The whole process develops in a single lightbeam, with no need of interferometers, and requires optical resources scaling linearly with the number of steps. Our demonstration introduces a novel versatile photonic platform for implementing quantum simulations, b...

The top polarization at the International Linear Collider (ILC) with transverse beampolarization is utilized in the + - → $t\\bar{t}$ process to probe interactions of the scalar and tensor type beyond the Standard Model and to disentangle their individual contributions. Confidence level limits of 90% are presented on the interactions with realistic integrated luminosity and are found to improve by an order of magnitude compared to the case when the spin of the top quark is not measured. Sensitivities of the order of a few times 10−3 TeV-2 for real and imaginary parts of both scalar and tensor couplings at $\\sqrt{s} = 500$ and 800 GeV with an integrated luminosity of 500 fb-1 and completely polarizedbeams are shown to be possible.

Seeking effective terahertz functional devices has always aroused extensive attention. Of particular interest is the terahertz beam splitter. Here, we have proposed, designed, manufactured, and tested a broadband non-polarizing terahertz beam splitter with a variable split ratio based on an all-dielectric metasurface. The metasurface was created by patterning a dielectric surface of the N-step phase gradient and etching to a few hundred micrometers. The conversion efficiency as high as 81% under the normal incidence at 0.7 THz was achieved. Meanwhile, such a splitter works well over a broad frequency range. The split ratio of the proposed design can be continuously tuned by simply shifting the metasurface, and the angle of emergences can also be easily adjusted by choosing the step of phase gradients. The proposed design is non-polarizing, and its performance is kept under different polarizations.

In this paper the focusing capability of a radiating aperture implementing an inward cylindrical traveling wave tangential electric field distribution directed along a fixed polarization unit vector is investigated. In particular, it is shown that such an aperture distribution generates a non-diffractive Bessel beam whose transverse component (with respect to the normal of the radiating aperture) of the electric field takes the form of a zero-th order Bessel function. As a practical implementation of the theoretical analysis, a circular-polarized Bessel beam launcher, made by a radial parallel plate waveguide loaded with several slot pairs, arranged on a spiral pattern, is designed and optimized. The proposed launcher performance agrees with the theoretical model and exhibits an excellent polarization purity.

Current and planned observations of the Cosmic Microwave Background (CMB) polarization anisotropies, with their ever increasing number of detectors, have reached a potential accuracy that requires a very demanding control of systematic effects. While some of these systematics can be reduced in the design of the instruments, others will be have to be modeled and hopefully accounted for or corrected a posteriori. We propose QuickPol, a quick and accurate calculation of the full effective beam transfer function and of temperature to polarization leakage at the power spectra level, as induced by beam imperfections and mismatches between detector optical and electronic responses. All the observation details such as exact scanning strategy, imperfect polarization measurements and flagged samples are accounted for. Our results are validated on Planck-HFI simulations. We show how the pipeline can be used to propagate instrumental uncertainties up to the final science products, and could be applied to experiments with...

In this contribution accelerator solutions for polarizedbeams and their impact on physics measurements are discussed. Focus are physics requirements for precision polarimetry near the interaction point and their realization with polarized sources. Based on the ILC baseline programme as described in the Reference Design Report (RDR), recent developments are discussed and evaluated taking into account physics runs at beam energies between 100 GeV and 250 GeV, as well as calibration runs on the Z-pole and options as the 1TeV upgrade and GigaZ. The studies, talks and discussions presented at this conference demonstrated that beampolarization and its measurement are crucial for the physics success of any future linear collider. To achieve the required precision it is absolutely decisive to employ multiple devices for testing and controlling the systematic uncertainties of each polarimeter. The polarimetry methods for the ILC are complementary: with the upstream polarimeter the measurements are performed in a clean environment, they are fast and allow to monitor time-dependent variations of polarization. The polarimeter downstream the IP will measure the disrupted beam resulting in high background and much lower statistics, but it allows access to the depolarization at the IP. Cross checks between the polarimeter results give redundancy and inter-calibration which is essential for high precision measurements. Current plans and issues for polarimeters and also energy spectrometers in the Beam Delivery System of the ILC are summarized in reference [28]. The ILC baseline design allows already from the beginning the operation with polarized electrons and polarized positrons provided the spin rotation and the fast helicity reversal for positrons will be implemented. A reversal of the positron helicity significantly slower than that of electrons is not recommended to not compromise the precision and hence the success of the ILC. Recently to use calibration data at the Z

We demonstrate the first light sheet microscope using propagation invariant, accelerating Airy beams that operates both in single- and two-photon modes. The use of the Airy beam permits us to develop an ultra compact, high resolution light sheet system without beam scanning. In two-photon mode, a...

Using the transverse Hertz vector potentials, vector analyses of linearly and circularly polarized Bessel beams of arbitrary orders are presented in this paper. Expressions for the electric and magnetic fields of vector Bessel beams in free space that are rigorous solutions to the vector Helmholtz equation are derived. Their respective time averaged energy density and Poynting vector are also obtained, in order to exhibit their non-diffracting properties. Polarization patterns and magnitude profiles with different parameters are displayed. Particular emphasis is placed on the cases where the ratio of wave number over its transverse component k/kt approximately equals to one and largely exceeds it, which corresponding to the nonparaxial and paraxial condition, respectively. These results allow us to recognize that the vector Bessel beams exhibit new and important features, compared with the scalar fields.

A kind of multi channel dual-core photonic crystal fiber polarizationbeam splitter is designed. We analyze the effects of the lattice parameters and the thickness of gold layer on the beam splitting by the finite element method. Numerical results show that the thickness of metal layer and the size of the air holes near the fiber cores are closely linked with the nature of the polarizationbeam splitter. We also obtain that extinction ratio can reach -73.87 dB at 1 . 55 μm wavelength and at 1 . 41 μm, 1 . 65 μm extinction ratio can reach 30.8978 dB and 31.1741 dB, respectively. The comparison of the effect on the characteristic of the photonic crystal fiber with coating no gold is also taken into account.

Multiple-degrees-of-freedom free-space communication combining polarization and high-order spatial modes promises high-capacity communication channel. While high-order spatial modes have been widely exploited for dense coding and high-dimensional quantum information processing, the properties of polarization preservation of high-order spatial beams propagating in turbulent atmosphere have not been comprehensively investigated yet. Here we focus on the properties of polarization preservation of partially coherent Hermite-Gaussian beams propagating along different atmospheric turbulence paths. The analytical expressions for the polarization of partially coherent Hermite-Gaussian beams propagating through atmospheric turbulence along different paths have been derived. It is shown that the larger the coherence length is, and the larger the beam order m, n are, the less the polarization is changed. We find that the evolution properties of the polarization in slant-down paths through turbulent atmosphere are simila...

The ability to control the position and orientation of nanorods in a device is interesting both from a scientific and a technological point of view. Because semiconductor nanorods exhibit anisotropic absorption, and spontaneous and stimulated emission, aligning individual NRs to a preferred axis is attractive for many applications in photonics such as solar cells, light-emitting devices, optical sensors, switches, etc. Electric-field-driven deposition from colloidal suspensions has proven to be an efficient method for the controlled positioning and alignment of anisotropic particles. In this work, we present a novel technique for the homogeneous deposition and alignment of CdSe/CdS NRs on a glass substrate patterned with transparent indium tin oxide interdigitated electrodes, with a spacing of a few micrometers. This method is based on applying a strong AC electric field over the electrodes during a dip-coating procedure and subsequent evaporation of the solvent. The reproducible and homogeneous deposition on large substrates is required for large size applications such as solar cells or OLEDs. The accumulation, alignment, and polarized fluorescence of the nanorods as a function of the electrical field during deposition are investigated. A preferential alignment with an order parameter of 0.92 has been achieved.

@@ Light frequency shift measured in a smalloptically pumped caesium beam frequency standard is reported and analysed. Two light sources, the diffused laser light scattered from the caesium beam tube parts and the fluorescence light from the beam atoms excited by the laser light, for the light frequency shift are discussed.

The experimental results recently obtained for fusion reactions at energies close to the Coulomb barrier with light radioactive (loosely bound) beams are reviewed and critically discussed. There have been two conflicting views on the effect of the loose binding of the projectile on the fusion cross section. On the one hand one expects an enhancement of the fusion cross section due to the loose binding while, on the other hand, the easy breakup of the projectile is expected to inhibit the fusion cross section. We critically discuss these two aspects of loose binding by comparing the experimental results for a number of radioactive beams. The data for sup 1 sup 7 F (where the last neutron binding energy S sub n =0.601 MeV), neither show breakup effects nor enhancement when compared with the fusion of the nucleus sup 1 sup 9 F. The data for a sup 6 He beam (S sub 2 sub n =0.975 MeV) show enhancement, very strong in one case, and the strong breakup (BU)+transfer cross section may be related to this. The fusion da...

Recent spectropolarimetric observations of Herbig AeBe stellar systems show linear polarization variability with wavelength and epoch near their obscured H-alpha emission. Surprisingly, this polarization is not coincident with the H-alpha emission peak but is variable near the absorptive part of the line profile. With a new and novel model we show here that this is evidence of optical pumping - anisotropy of the incident radiation that leads to a linear polarization-dependent optical depth within the intervening hydrogen wind or disk cloud. This effect can yield a larger polarization signal than scattering polarization in these systems.